base
base — verb
1. to use a particular city, country, or building as the centre from which a person
to use a particular city, country, or building as the centre from which a person lives or runs their work, with most travel and activity starting and ending there.
Yusuf is based in Taipei but flies to Tokyo for client meetings most weeks.
passive: be based in [city]
The charity bases its rescue teams at a small airfield near the coast.
active: base [object] at [place]
After the merger, the design team will be based in the Berlin office full time.
Linnea works for a Spanish bank and is currently based in Singapore.
The film crew based themselves in a small village for the whole shoot.
reflexive: base oneself in [place]
- be based in
- be based at
- based abroad
- permanently based
- headquartered
more formal; only used of organisations, not individuals
- stationed
usually military or official postings rather than ordinary work
- located
describes physical position; less about where someone operates from
Grammar Patterns
be based in [place]
be based at [location]
Usage Note
Most often appears in the passive (be based in / at) when describing where a person or company normally operates from. The active form usually takes a company, team, or organisation as the subject.
Common Mistakes
2. to build a story, decision, theory, or product by drawing its main ideas, facts,
to build a story, decision, theory, or product by drawing its main ideas, facts, or shape from another source — for example, a film built around a real event, or a price worked out from sales figures.
The director based the film on a true story about a young swimmer from Korea.
active: base [X] on [source]
Our prices are based on the cost of cotton, so they change every season.
passive: be based on [factor]
Olu based her novel on letters her grandmother wrote during the war.
The judge said the ruling was based entirely on written evidence from both sides.
adverb: based entirely on
You should not base such an important decision on a single phone call.
- based on a true story
- based on evidence
- base a decision on
- loosely based on
Grammar Patterns
base [something] on [something]
be based on [source]
Usage Note
Almost always followed by 'on' (sometimes 'upon' in formal writing). Distinguish from sense 1 (WORK FROM PLACE): sense 2 takes an abstract object such as a story, decision, or theory, while sense 1 takes a person, team, or company plus a physical location.
Common Mistakes
base — noun
1. the flat or supporting underside of a physical object — the part it stands on or
the flat or supporting underside of a physical object — the part it stands on or that holds it up, such as the underside of a lamp, vase, or column.
Yusuf glued a thick felt pad to the base of the wooden lamp so it would not scratch the table.
the base of [object]: typical possessive frame
The tall vase tipped over because its base was too narrow for its height.
subject = inanimate object's stability feature
Dr. Lin tapped the base of the microscope to show students where the light enters.
Hikers stopped to rest at the base of the cliff before climbing higher.
extended use: 'base of the cliff/mountain'
There was a small crack running across the base of the coffee mug.
- the base of the cliff
- wide base
- narrow base
- rest on a base
- circular base
- bottom
more everyday; refers to the lowest surface generally
- foot
used for tall things like mountains, ladders, stairs
- foundation
implies a built support that carries weight, often for buildings
Grammar Patterns
the base of [object]
Usage Note
Object is almost always a concrete physical thing (lamp, statue, column, mountain). Distinguish from sense 7 (MAIN INGREDIENT), which describes the principal substance or layer of a mixture rather than a literal underside.
Common Mistakes
2. the central location that a person treats as home or a company runs its activiti
the central location that a person treats as home or a company runs its activities from, and that they regularly return to.
Nikolai uses Taipei as his base while he travels around Asia for work.
use [place] as a base — common collocation
The small design studio has its base in an old warehouse near the river.
have one's base in [location]
After ten years in Berlin, the family decided to move their base back to Lisbon.
The charity runs from a tiny base above a bakery in the old town.
Many remote workers choose Lisbon as a base because flights to other cities are cheap.
- use as a base
- operate from a base
- have a base in
- permanent base
- temporary base
- headquarters
more formal; usually a company's main office
- home
everyday; more about living than business
- centre
wider — any focal point of activity
Grammar Patterns
[someone/company]'s base in [location]
use [place] as a base
Usage Note
Often used with 'use … as a base' or 'have a base in [city]'. Distinguish from sense 3 (MILITARY): sense 2 covers civilian work or daily life; sense 3 is specifically a place run by armed forces.
Common Mistakes
3. a fixed site belonging to an army, navy, or air force, where soldiers are housed
a fixed site belonging to an army, navy, or air force, where soldiers are housed and where missions and supplies are organised.
Captain Reyes was stationed at an air base in northern Italy for three years.
stationed at a base — passive military pattern
Trucks loaded with food and medicine rolled out of the army base before dawn.
The naval base near the harbour has been closed to visitors for security reasons.
compound: naval base / air base / army base
Lt. Park returned to the base after a long patrol in the desert.
Two soldiers were guarding the main gate of the base when we arrived.
- army base
- naval base
- air base
- military base
- return to base
- stationed at the base
Grammar Patterns
a [type] base
stationed at a base
Usage Note
Almost always appears with a qualifier showing the branch — 'army base', 'naval base', 'air base', 'military base'. Distinguish from sense 2 (MAIN PLACE), which is civilian; this sense is exclusively about armed forces.
Common Mistakes
4. in baseball or softball, any of the four marked spots on the diamond that a runn
in baseball or softball, any of the four marked spots on the diamond that a runner has to step on so a run will count.
Linnea slid into second base just before the ball reached the fielder.
slide into [ordinal] base — typical action verb
Mia hit the ball to the wall and ran all the way around the bases for a home run.
run around the bases — common phrase
The runner on first base watched the pitcher carefully, ready to steal.
runner on [ordinal] base
After three balls, the batter walked to first base.
Coach Dimitri tells the kids to keep their eyes on the ball as they round each base.
- first base
- second base
- third base
- reach base
- steal a base
- load the bases
Grammar Patterns
reach base
steal a base
Usage Note
Almost always with an ordinal number — 'first base', 'second base', 'third base' (home plate is the fourth). Found in fixed phrases like 'reach base', 'steal a base', 'load the bases'.
Common Mistakes
5. an idea, fact, or earlier piece of work that becomes the starting point others b
an idea, fact, or earlier piece of work that becomes the starting point others build on when developing a theory, plan, or argument.
Maria's village interviews became the base for her doctoral thesis on rural healthcare.
the base for + noun (project / argument)
The detective used the witness statements as the base of her whole investigation.
the base of + noun
Five years of sales records gave the new managers a solid base to plan from.
a solid / strong base to + verb
Without good evidence, the lawyer had no base for her surprising claim.
no / a / some base for + abstract noun
The novel takes Greek myths as a base and turns them into modern stories about office workers.
take X as a base
- solid base
- strong base
- the base of an argument
- form the base for
- basis
more common in the fixed phrases 'on the basis of' and 'have no basis'; 'base' is preferred when the starting point is a tangible body of work.
- foundation
stronger and more abstract; suggests the whole later structure depends on it.
- groundwork
emphasises preparatory work already done, not just the idea behind it.
Grammar Patterns
the base for + noun
the base of + noun
Usage Note
Distinguish from sense 7 (MAIN INGREDIENT): sense 7 names the largest physical or structural component of something; sense 5 names an intellectual starting point that further work develops out of. Often paired with abstract nouns like 'theory', 'argument', 'plan', 'thesis'.
Common Mistakes
6. the group of people, customers, or supporters that an organisation, politician,
the group of people, customers, or supporters that an organisation, politician, or business depends on for most of its money, votes, or backing.
The senator's loyal base of older voters helped her win the election by a wide margin.
[someone's] base of [supporter type]
The brand built its customer base through small, friendly shops rather than big advertising.
customer base — strong collocation
Many young artists have a strong fan base on social media before they sign a record deal.
fan base — strong collocation
The mayor lost touch with his working-class base after moving to a wealthy neighbourhood.
The party is trying to expand its base among younger voters in the cities.
expand the base — common action verb
- customer base
- fan base
- voter base
- tax base
- loyal base
- expand the base
- following
wider; any group of admirers, not just paying or voting
- supporters
everyday plural; less abstract
- constituency
formal; mostly political contexts
Grammar Patterns
a [type] base
[someone]'s [type] base
Usage Note
Frequently appears in compounds: 'customer base', 'fan base', 'voter base', 'tax base'. Distinguish from sense 7 (MAIN INGREDIENT): sense 6 is always a group of people; sense 7 is a substance, layer, or main ingredient.
Common Mistakes
7. the chief substance or first layer in a mixture, dish, or product, to which othe
the chief substance or first layer in a mixture, dish, or product, to which other ingredients or coats are added.
Chef Olivia made a rich pasta sauce with a base of slow-cooked tomatoes and garlic.
a base of [substance] — defining frame
Most of these face creams use water as their base, with oils added for softness.
[substance] as a base
The painter spread a thin white base on the canvas before adding the bright colours.
This salad dressing has a base of olive oil mixed with lemon juice and honey.
Many traditional Thai curries start from a base of fresh chillies, lemongrass, and garlic.
- a base of
- oil-based
- water-based
- tomato-based
- creamy base
- rich base
- foundation
more abstract; can also be used for cosmetics layers
- core
stresses centrality rather than the bottom layer
Grammar Patterns
a base of [substance]
[substance]-based
Usage Note
Common in cooking, cosmetics, and painting contexts. Often followed by 'of + substance'. Compound 'X-based' is very productive: 'oil-based', 'water-based', 'tomato-based'. Distinguish from sense 6 (SUPPORT GROUP), which is always people, not substances.
Common Mistakes
8. in a counting system, the size of the group that the place values are organised
in a counting system, the size of the group that the place values are organised around — for example, every tenth value in our everyday numbers, or every second value when computers count using only 0 and 1.
Most people count in base 10, using the digits 0 through 9 in each place.
count / work in + base + number
Computers store all data in base 2, where every digit can only be 0 or 1.
in base 2 (binary)
Programmers often write memory addresses in base 16 to keep them short and easy to read.
in base 16 (hexadecimal)
The teacher asked the class to convert the number 27 from base 10 into base 2.
convert from base X into base Y
Ancient Babylonian astronomers used a base of 60, which is why we still have 60 minutes in an hour.
a base of + number
- base 10
- base 2
- base 16
- convert to base
- in base + number
- radix
the technical term used in computer science papers; rare in everyday speech.
Grammar Patterns
base + number (e.g. base 10, base 2)
Usage Note
Almost always followed directly by a number ('base 10', 'base 2', 'base 16'), with no article between. The article appears in the longer pattern 'a base of + number' when describing the system in general.
Common Mistakes
9. a substance such as ammonia or sodium hydroxide which, when mixed into water, ne
a substance such as ammonia or sodium hydroxide which, when mixed into water, neutralises an acid and produces a salt; bases feel slippery and turn red litmus paper blue.
In the lab, Dr. Dimitri added a weak base to the acid until the colour changed to green.
a weak / strong base
Soap feels slippery on your fingers because it contains a mild base.
contain / be a base
Acids and bases react together to form a salt and water.
acids and bases (paired)
The students tested several household liquids and found that bleach acts as a strong base.
act as a base
Sodium hydroxide is the base most often used to make industrial soap.
[chemical name] is a base
- a strong base
- a weak base
- acids and bases
- act as a base
- alkali
in school chemistry, often used for bases that fully dissolve in water; technically a subset of bases.
- acid
the opposite chemical type; an acid releases hydrogen ions while a base accepts them.
Usage Note
Almost always appears in the paired phrase 'acids and bases' in school chemistry. The plural 'bases' in this sense is a homograph with the plural of sense 4 (baseball) — context normally makes the meaning clear.
Common Mistakes
off base
idiomcompletely wrong about something, or far from the correct answer or judgement.
Theo was way off base when he guessed that his sister had eaten the last cookie.
The newspaper's report on the new law turned out to be totally off base.
to get in contact with someone briefly, often to share news or check how things are going.
I'll touch base with Olu tomorrow to see how the new project is going.
Let's touch base after lunch and decide what to do about the missing files.
cover all the bases
idiomto think about and prepare for every possible part of a situation so that nothing important is missed.
Before the big presentation, Aiko made a checklist to cover all the bases.
Our lawyer covered all the bases in the contract, from late payments to early cancellation.
To fail to make any progress at the beginning of something.
Sara tried to start a conversation with Diego, but she didn't get to first base.
Min's project proposal didn't get to first base with the committee.
To contact someone briefly to share information or check in.
Brian called his manager to touch base about the new client.
Let's touch base next week to see how the project is going.
base — adjective
1. describing the simplest version of a product or system, before any extra feature
describing the simplest version of a product or system, before any extra features, upgrades, or higher-priced options are added.
The base model of this laptop comes with 8 GB of memory and no extra software.
collocation: base model / base version
Olu chose the base trim of the SUV because she did not want leather seats.
collocation: base trim (cars)
Tickets start at the base price of 800 yuan, with better seats costing more.
collocation: base price / base rate / base salary
Engineers tested the base design first, then added the new safety features.
Yuki's base salary is fixed, but her yearly bonus depends on team results.
- base model
- base version
- base price
- base rate
- base salary
- base trim
- basic
more common everyday word; covers the same 'no extras' idea
- entry-level
marketing term; the cheapest model aimed at first-time buyers
- standard
the default version supplied without optional add-ons
Grammar Patterns
base + noun
Usage Note
Almost always used before a noun (attributive), especially with words for products, prices, and pay: 'base model', 'base price', 'base salary', 'base rate'. Distinguish from sense 2 (WITHOUT HONOUR): this sense is about cost or features, not morality.
Common Mistakes
2. behaving in a way that lacks moral standards, kindness, or any sense of decency,
behaving in a way that lacks moral standards, kindness, or any sense of decency, especially when acting from selfish or shameful motives.
Stealing money from a sick neighbour was a base act that shocked the whole village.
noun phrase: a base act / a base motive
The novel's villain betrays his oldest friend for gold, driven by base greed.
collocation: base greed / base instincts
Clara accused the politician of base lies designed to ruin her family.
It was base of Theo to laugh at the children who had lost their home.
pattern: base of [someone] to [do something]
The judge said few crimes were as base as cheating an elderly widow out of her savings.
- base motive
- base instincts
- base greed
- base lies
- a base act
- ignoble
very formal, often literary; same idea of low moral worth
- dishonourable
everyday formal word, focuses on breaking codes of honour
- despicable
stronger; suggests the action deserves open contempt
- shameful
more common; emphasises that the actor should feel shame
- noble
showing high moral character, often paired with 'base' as its opposite
- honourable
everyday opposite, acting from principle
Usage Note
Largely literary or formal in modern English; in everyday speech, words like 'shameful', 'dishonourable', or 'mean' replace it. Often appears before abstract nouns such as 'motive', 'instinct', or 'greed' rather than describing people directly.
Common Mistakes
Word family
Synonym discussion
Sense: noun/2
All four words point to a place that someone or some group regularly works from, but they fit different contexts. 'Base' is the most flexible: it can be the city a freelance journalist returns to between trips, the small office a charity runs from, or the country a multinational treats as its main operating point. 'Headquarters' is more formal and corporate — the single principal office that directs a whole organisation, often a large one ('the company's headquarters in Frankfurt'). 'Centre' is wider still and stresses focal activity rather than residence ('a research centre', 'the centre of operations') and often pairs with a topic word. 'Home' is the everyday choice for an individual's daily living place; using it for a company sounds figurative. So a designer might say 'Lisbon is my base', a CEO would refer to 'our headquarters in Tokyo', a scientist works at 'the marine research centre', and a student calls a dorm room 'home'.
Common collocations
Nouns
- customer base
- fan base
- voter base
- tax base
- base model
- base price
- base salary
- air base
- naval base
- army base
Adverbs
- permanently based
- currently based
- loosely based
- entirely based
Phrases
- use [place] as a base
- off base
- touch base
- cover all the bases
- based on a true story
Prepositions
- based in [city/country]
- based at [site]
- based on [source]
- the base of [object]
- a base for [project]
Etymology
The noun 'base' came into English in the 1300s from Old French 'base' and directly from Latin 'basis', meaning 'foundation' or 'pedestal', which itself was borrowed from Greek 'basis', literally 'a step' (from the verb meaning 'to walk' or 'to step on'). From this root grew the senses of physical bottom, supporting structure, and starting point for ideas — all the modern noun uses trace back to that image of something firm to step or stand on. The adjective 'base', meaning 'low in moral worth', has a separate origin: it comes from Old French 'bas' ('low'), from Late Latin 'bassus' ('short, low'). The two streams looked alike and merged in spelling, which is why modern English uses one word for both 'foundation' and 'shameful' meanings.