solid
solid — noun
1. A physical object like a cube, ball, or pyramid that has depth in addition to he
A physical object like a cube, ball, or pyramid that has depth in addition to height and width, so it is not flat.
The children learned to identify different solids like cubes and cylinders in maths class.
countable: solid + of + geometric shape
A sphere is a round solid; surface points sit equally far from the centre.
Architects often work with simple solids before adding details to a building design.
professional context: work with solids
The teacher showed the class a cardboard model of a solid called a hexagonal prism.
In art class, students drew still-life pictures using basic solids like cones and blocks.
- geometric solid
- regular solid
- simple solid
- solid shape
- three-dimensional figure
more formal, used in mathematical writing
- geometric body
technical term, common in geometry textbooks
- plane figure
a flat shape with only two dimensions
Grammar Patterns
solid + of + specific geometric shape
Usage Note
Countable only — you can say "a solid" or "solids" to refer to individual three-dimensional shapes. Common in geometry and design.
Common Mistakes
2. A material that keeps its shape and does not flow like a liquid or spread out li
A material that keeps its shape and does not flow like a liquid or spread out like a gas — for example, ice, stone, or iron.
Water turns into a solid when the temperature drops below zero degrees Celsius.
science context: liquid turns into solid
Most metals are hard solids at room temperature, but mercury is a liquid.
The students compared how a solid, a liquid, and a gas behave inside different containers.
contrast: solid vs liquid vs gas
Wood is a natural solid that people have used in homes for thousands of years.
When you freeze fruit juice, it changes from a liquid into a solid.
- from liquid to solid
- solid state
- solid form
- becomes a solid
- hard substance
less technical, focuses on the firmness property
- solid matter
formal term from physics and chemistry
Grammar Patterns
solid + verb
Usage Note
Can be countable ("different solids have different densities") or uncountable ("the solid was heated until it melted"). Often contrasted with liquid and gas in science contexts.
Common Mistakes
3. Food that you chew and swallow, such as bread, rice, or cooked vegetables — ofte
Food that you chew and swallow, such as bread, rice, or cooked vegetables — often used when discussing what babies or sick people can eat.
The doctor said the patient could start eating solids again after the operation.
medical context: start eating solids
Babies usually begin to eat solid foods when they are about six months old.
After a week of soup and juice, Noa was happy to eat solid food again.
contrast: liquid diet vs solid food
The hospital menu offers both liquid meals and solid foods for different patients.
Parents should introduce one new solid food at a time to check for allergies.
- solid foods
- eat solids
- solid food
- solid food
the full phrase, more common than the noun alone in everyday speech
- liquid
food in drinkable form, such as soup or juice
Grammar Patterns
eat + solids
feed + solids
Usage Note
Often appears in the plural ("solids") in medical and parenting contexts. The adjective phrase "solid food" is more common than the noun "a solid" in everyday conversation.
Common Mistakes
solid — adjective
1. Something that is not soft and keeps its shape when you press on it.
Something that is not soft and keeps its shape when you press on it.
Jabari knocked on the wall and it felt solid, not like cheap plasterboard.
predicative: felt solid
A solid mattress gives your back the support it needs while you sleep.
attributive: solid + noun
The ground was too solid for Nikhil to dig a hole with his bare hands.
The old library was built with thick, solid stone walls that kept the noise out.
Diya sat on the solid wooden bench and waited for the bus to arrive.
- solid ground
- solid surface
- solid wood
- solid stone
Grammar Patterns
solid + noun
be + solid
Usage Note
Only used with concrete subjects (objects, surfaces); for abstract reliability see sense 6 (RELIABLE).
Common Mistakes
2. Made of one piece of material all the way through, with no empty spaces, gaps, o
Made of one piece of material all the way through, with no empty spaces, gaps, or bubbles inside.
The door was made of solid oak, not thin wood with a hollow centre.
attributive: solid + material noun
Feng's house has solid brick walls that do not need extra insulation.
A solid rubber ball bounces much higher than one that has air inside it.
The sculptor carved the statue from a solid block of white marble.
These shoes have solid leather soles that will last for many years.
- solid oak
- solid brick
- solid rubber
- solid block
- solid leather
- solid wall
Grammar Patterns
solid + noun
be + solid
Usage Note
Commonly used with materials (wood, stone, metal, brick, rubber) to mean the object is made entirely of that substance.
Common Mistakes
3. Made of a single substance or a single colour, with nothing else added or mixed
Made of a single substance or a single colour, with nothing else added or mixed in.
Ramon wears a necklace made of solid gold that belonged to his grandmother.
attributive: solid + [metal]
The living room wall was painted a solid white for a clean, modern look.
attributive: solid + [colour]
Selim prefers solid colours when choosing curtains for his apartment.
The ring is not solid silver — it has a thin layer of silver over steel.
Otiso chose a solid blue shirt without any stripes or patterns on it.
- solid gold
- solid silver
- solid colour
- solid blue
Grammar Patterns
solid + [material / colour]
Usage Note
Almost always appears before the material or colour noun: 'solid gold', 'solid red'. Not used predicatively — 'The gold is solid' would be understood as sense 1 (firm) or sense 2 (without holes), not this sense.
Common Mistakes
4. In a firm, hard state that is not a liquid or a gas.
In a firm, hard state that is not a liquid or a gas.
Water turns into solid ice when the temperature drops below zero degrees.
turn + solid: change of state
The factory produces solid fuel for heating homes during the winter.
Eric put the solid waste from the kitchen into the compost bin outside.
When the lava cooled, it changed from a hot liquid into solid rock.
The chemist studied how the gas formed a solid layer inside the glass tube.
- solid fuel
- solid waste
- solid state
- solid rock
- solid ice
- frozen
specifically for liquids turned solid by cold; narrower than 'solid'
Grammar Patterns
solid + noun
turn / become + solid
Usage Note
Often contrasted with 'liquid' or 'gas' in scientific and practical contexts. 'Turn solid' and 'become solid' are common change-of-state patterns.
5. Describes food that is not liquid — used when talking about babies or people rec
Describes food that is not liquid — used when talking about babies or people recovering from illness who can start eating regular meals after having only liquids.
After the operation, Otis could not eat any solid food for two days.
collocation: solid food
The doctor told Amihan to start with soup before trying solid meals.
Babies usually begin eating solid food when they are about six months old.
After her surgery, Amira asked the nurse when she could start eating solid food again.
collocation: solid food
The hospital gave Christopher solid meals once he was feeling much better.
- solid food
- solid meal
- start solid food
- regular
more general; 'regular food' means normal meals as opposed to a special diet
- liquid
food in drinkable form, such as soup or juice
Grammar Patterns
solid + food / meal
Usage Note
Almost always used before 'food' or 'meal'. The noun plural 'solids' ('the patient cannot eat solids') is also common in medical contexts.
Common Mistakes
6. Strong, well-made, or well-reasoned enough to be trusted and depended on — for e
Strong, well-made, or well-reasoned enough to be trusted and depended on — for example, a solid reputation, solid evidence, or a solid plan.
Eitan's company has a solid reputation for treating its workers fairly.
collocation: solid reputation
The police found solid evidence that proved the man was not guilty.
collocation: solid evidence
Ingrid gave a solid performance in the final exam and scored very high.
After years of hard work, the business was built on a solid financial base.
Feng did not have solid proof, so the judge asked him to bring more facts.
- solid reputation
- solid evidence
- solid performance
- solid base
- solid understanding
- solid plan
- reliable
can be counted on to work or behave well; very close in meaning
- dependable
will not let you down; slightly more personal
- sound
well-reasoned or in good condition; common with 'argument' and 'judgement'
- strong
less formal; broadly similar across concrete and abstract uses
- unreliable
cannot be trusted to work well or be correct
- weak
not strong or convincing, especially of evidence or arguments
Grammar Patterns
solid + abstract noun
be + solid
Usage Note
Commonly modifies abstract nouns: 'reputation', 'evidence', 'plan', 'argument', 'performance', 'understanding'. Avoid using with concrete objects (use sense 1 instead).
Common Mistakes
7. continuing without any pause or break, and usually lasting for a noticeably long
continuing without any pause or break, and usually lasting for a noticeably long amount of time.
Eitan studied for four solid hours before his final exam.
solid + [time unit] for continuous duration
The rain fell for three solid days and flooded the streets.
After a solid week of rain, the river rose above its banks.
collocation: solid week / solid month
The Watanabe family drove for ten solid hours to reach their grandmother's house.
Benjamin worked on the report for two solid months without taking any days off.
- solid hour
- solid day
- solid week
- solid month
- solid year
- continuous
more formal; 'solid' carries a stronger sense of impressively long duration
- unbroken
emphasises the absence of interruptions
- straight
used with time periods in informal US English: 'three straight hours'
- broken
interrupted or with pauses
- intermittent
stopping and starting again
Grammar Patterns
solid + [time unit]
Usage Note
Used only before a noun (attributive), and typically paired with units of time such as hours, days, weeks, or months.
Common Mistakes
8. having length, width, and depth, rather than being flat like a drawing or a phot
having length, width, and depth, rather than being flat like a drawing or a photograph.
In geometry class, the students learned to calculate the volume of a solid figure.
collocation: solid figure / solid shape
A cube is a solid shape with six equal square faces.
Folake's art project required her to create a solid object from clay.
Unlike a flat drawing on paper, a solid form has depth that you can measure.
contrasting solid with flat / two-dimensional
Dewi built a small solid model of the house before starting construction.
- solid figure
- solid shape
- solid object
- solid form
- solid geometry
- three-dimensional
the more explicit term; 'solid' is shorter and more common in mathematical contexts
- cubic
narrower — refers specifically to cube-like shapes
- spatial
relates to space generally; less commonly paired with 'figure' or 'shape'
- flat
having only two dimensions
- two-dimensional
explicitly lacking depth
Grammar Patterns
solid + [shape / figure / object]
Usage Note
Chiefly used in geometry, mathematics, and design contexts. Not to be confused with sense 1 (HARD / FIRM) — an object described as 'solid' in this sense may be soft or hollow; only its dimensionality matters.
Common Mistakes
9. with every member of a group sharing the same opinion, giving complete and unite
with every member of a group sharing the same opinion, giving complete and united support or opposition.
The committee was solid in its decision to reject the proposal.
pattern: solid in + decision / opinion / support
Saira's entire family was solid in their support of her decision to study abroad.
collocation: solid support
The union members stood solid behind their leader during the negotiations.
pattern: solid behind + person / group
Hassan received solid backing from every member of the board.
The town was solid in its opposition to the new highway plan.
- solid support
- solid backing
- solid agreement
- solid opposition
- solid behind
Grammar Patterns
solid in + [noun phrase]
solid behind + [noun phrase]
Usage Note
Often followed by 'in' (indicating the matter agreed on) or 'behind' (indicating the person or group supported). Distinguish from sense 6 (RELIABLE) — 'solid support' here means unanimous, not merely dependable.
Common Mistakes
solid as a rock
idiomExtremely firm, strong, or reliable — used for both physical objects and abstract things like relationships or plans.
After ten years, Christopher and Diya's marriage is still solid as a rock.
The old bridge is built on pillars that are solid as a rock even after a hundred years.
To have strong and correct reasons for your opinion or argument.
Maya was on solid ground when she criticized the budget plan.
Are you on firm ground with your claim about the test results?
solid — adverb
1. in a firm, strong, or complete way — for example, standing solid to show you wil
in a firm, strong, or complete way — for example, standing solid to show you will not change your mind, or voting solid to show complete agreement with a group.
The whole team stood solid behind their captain during the crisis.
stand + solid (remain firm/unwavering)
Gabriela slept solid for nine hours after three nights of little rest.
sleep + solid (continuously, without waking)
The union members voted solid against the company's new contract offer.
vote + solid (unanimously, all together)
You can count on Lien — she stands solid with her friends no matter what.
The committee backed the proposal solid, with no one raising any objections.
- stand solid
- vote solid
- sleep solid
- back solid
- remain solid
- weakly
opposite of firmness or strength
Grammar Patterns
stand + solid
vote + solid
sleep + solid
support + solid
Usage Note
This is a flat adverb — the -ly form 'solidly' is more common in formal or written English. 'Solid' as an adverb is informal and typically appears in fixed combinations such as 'stand solid', 'vote solid', or 'sleep solid' (chiefly British).
Common Mistakes
Word family
- solidlyadverbB2
- soliditynounB2
- solidifyverbB2
- solidificationnounC1
- solidaritynounB2
- consolidateverbB2
- consolidationnounC1
Synonym discussion
Sense: adjective/1
These words all describe something that does not change shape easily, but they differ in scope and typical use. 'Solid' suggests the whole object is dense and unbreakable (a solid oak table). 'Firm' means something gives only slightly under pressure but then holds, often used for cushions, mattresses, or ground (a firm handshake). 'Hard' focuses on the surface not being soft, without implying anything about the inside (a hard floor). 'Sturdy' describes something built well enough to survive heavy use without breaking (a sturdy backpack). 'Strong' is broader and can describe physical objects (a strong rope), abstract qualities (a strong argument), or intensity (a strong smell). For physical objects that feel dense throughout, use 'solid' or 'sturdy'; for surface firmness, use 'firm' or 'hard'; for general durability, use 'sturdy' or 'strong'.
Common collocations
Adverbs
- completely solid
- perfectly solid
- fairly solid
- rock solid
Phrases
- solid as a rock
- on solid ground
- solid footing
- solid foundation
Prepositions
- solid as
- solid in
- solid behind
Etymology
The word 'solid' entered English from Latin 'solidus', meaning firm, whole, or dense. In Old French it became 'solide', and Middle English borrowed it as 'solid' during the 14th century. The Latin root also gave us related words like 'consolidate' (to make firm together), 'solidarity' (unity based on shared interests), and 'solidify' (to become firm). The abstract senses — reliable, unanimous, continuous — developed later from the core physical meaning of something dense and unshakeable.