code
code — noun
1. any system of signs, characters, or digits that lets people pass hidden meaning
any system of signs, characters, or digits that lets people pass hidden meaning between one another, or present data in a condensed way
The spy sent all messages in code so that enemy agents could not read them.
in code — using a secret communication system
Each item in the warehouse has a bar code that a scanner can read instantly.
bar code — product identification system
Aiko learned Morse code during a summer survival course and still recalls the dots and dashes.
The hospital gives every new patient a unique identification code on their wristband.
identification code — system for identifying items or people
The area code for Tokyo is 03, so you must dial that before the local number.
- break a code
- crack a code
- Morse code
- bar code
- area code
- in code
- postal code
- cipher
specifically a method of transforming a message to hide its meaning; more technical than code
- symbol system
broader; refers to any set of symbols that convey meaning, not necessarily secret
- plain text
a message in its original, readable form before being put into code
Grammar Patterns
code + for + noun
in code
Usage Note
Countable for individual systems (a secret code, a bar code); uncountable when referring to the concept of using codes (information sent in code).
Common Mistakes
2. a collection of written regulations that govern the behaviour of members inside
a collection of written regulations that govern the behaviour of members inside a particular profession, organization, or country
All doctors must follow the medical code of conduct when treating patients.
code of conduct — rules for professional behaviour
The company introduced a new dress code that requires formal wear from Monday to Thursday.
dress code — rules about what to wear
Lawyers who break the professional code can lose their licence to practise law.
The building code in this city requires every office to have two emergency exits.
building code — safety rules for construction
Leila studied the tax code carefully before filing her company's annual return.
- code of conduct
- code of practice
- dress code
- building code
- penal code
- tax code
- professional code
- regulations
more formal and specific; regulations are often enforceable by law
- guidelines
less strict than a code; guidelines are suggestions rather than binding rules
Grammar Patterns
code of + noun
code for + noun
Usage Note
Commonly followed by 'of' (code of conduct, code of practice) or used as a compound noun (dress code, building code, penal code). When referring to law, often used with 'the' + specific jurisdiction (the German civil code).
Common Mistakes
3. a set of personal or social beliefs about what is right and wrong, which guides
a set of personal or social beliefs about what is right and wrong, which guides how a person or a group behaves
According to their moral code, telling a lie is never acceptable even when it helps.
moral code — personal beliefs about right and wrong
Honour is a central value in the samurai code of behaviour.
Each culture has its own unwritten code of politeness that visitors should try to learn.
unwritten code — social expectations not written down
His personal code prevented him from cheating on the exam even though nobody was watching.
The code of honour among the old fishermen meant they always shared their catch equally.
code of honour — principles based on personal integrity
- moral code
- code of honour
- code of ethics
- personal code
- unwritten code
- ethics
more formal and often refers to a philosophical system; 'code' is more personal and practical
- principles
broader; principles are fundamental beliefs that may form a code
Grammar Patterns
code of + noun
Usage Note
Unlike sense 2 (RULES), this sense refers to unwritten, often personal principles rather than official written regulations. Frequently appears with personal possessives (his code, their code) or in phrases like 'code of honour' and 'moral code'.
4. a set of instructions written in a programming language that tells a computer wh
a set of instructions written in a programming language that tells a computer what operations to perform
Theo spent the whole weekend writing code for his new mobile game.
writing code — creating computer programs
A small mistake in the code caused the website to show the wrong prices.
Learning to read and write code is now a useful skill for many jobs outside technology.
read and write code — understanding and creating programming instructions
Rohan reviewed the code and found several places where it could run much faster.
The team wrote thousands of lines of code to build the navigation system for the drone.
lines of code — unit for measuring program size
- write code
- lines of code
- piece of code
- source code
- machine code
- code base
- run code
- source code
specifically the human-readable version of code before it is compiled
- programming instructions
more general and descriptive; explains the concept to non-specialists
Grammar Patterns
write code
code + verb
Usage Note
Usually uncountable (the code, some code, lines of code) but countable when referring to a specific program or section (this piece of code, the code for the login page).
Common Mistakes
5. the complete set of biological instructions stored in DNA that gives a living th
the complete set of biological instructions stored in DNA that gives a living thing its characteristics and controls how its body works
Scientists have successfully mapped the entire genetic code of the wheat plant.
genetic code — the biological information in DNA
A tiny change in the genetic code can sometimes cause a serious medical condition.
The team compared viral genetic code from different countries to track its spread.
The genetic code of this dog breed explains why it grows such a thick winter coat.
genetic code of + species — the DNA instructions for a particular organism
All living things on Earth share the same basic genetic code made from four chemical letters.
- genetic code
- genetic code + verb (determine, control, produce)
- human genetic code
- genome
refers to the entire set of genetic material, while 'genetic code' refers specifically to the rules by which it works
- DNA sequence
the specific order of chemical units in DNA
Grammar Patterns
genetic code
Usage Note
Almost always appears in the phrase 'genetic code' in biology. The term 'code' alone is rarely used in this sense without 'genetic' modifying it.
6. a particular variety of language used by a specific group of people, or a system
a particular variety of language used by a specific group of people, or a system of words that only insiders understand
The children created a secret code using made-up words that their parents could not follow.
Linguists are working to document the spoken code used by older members of the fishing community.
spoken code — a language variety used by a particular group
The academic code in her paper was too full of specialist terms for a general reader.
Yara learned the local code of hand signals that market traders used to communicate from a distance.
code of hand signals — a non-verbal communication system
Teenagers in the school developed their own code of slang that confused the new teachers.
code of slang — informal vocabulary shared by a group
- secret code
- spoken code
- code-switching
- code of slang
Usage Note
This sense overlaps with the COMMUNICATION SYSTEM sense (sense 1) but focuses specifically on language and dialect varieties rather than secret or technical encoding. It is less common in everyday speech and appears mostly in linguistics or social commentary.
code — verb
1. to transform a message into symbols that only its intended recipient has the too
to transform a message into symbols that only its intended recipient has the tools to decode
The general ordered his team to code the message before sending it to the front-line base.
Diego learned how to code simple messages using a substitution cipher during his training.
code + noun phrase — convert information into code
The software automatically codes any sensitive customer data before storing it on the server.
All patient records are coded so that private medical information stays protected.
passive: are coded — often used in passive voice
The agent coded the meeting coordinates into a series of innocent-looking song lyrics.
code + into — convert into a different form for secrecy
- code a message
- code data
- code information
- code + into
- code + as
Grammar Patterns
code + noun phrase
code + noun phrase + as + noun phrase
Usage Note
Frequently used in the passive voice (the message was coded). Contrast with 'encode', which is more technical and more common in computing contexts.
Common Mistakes
2. to write instructions in a programming language that a computer can follow to pe
to write instructions in a programming language that a computer can follow to perform tasks
Hana started learning to code when she was twelve years old.
intransitive: to code — write computer programs as an activity
The team coded a new feature that lets users share photos with one tap.
transitive: code + noun phrase — write a specific program
Priya coded the entire search algorithm in less than a week.
Many online courses now teach adults who want a career change how to code from scratch.
Kofi codes mobile games that have been downloaded over a million times around the world.
- code an app
- code a website
- code software
- code in Python/Java
- learn to code
- code from scratch
Grammar Patterns
code (intransitive)
code + noun phrase (transitive)
Usage Note
Can be used intransitively (she codes for a living) or transitively (he coded an app). The intransitive use emphasizes the activity; the transitive use emphasizes the product. This is the most common verb sense in everyday modern English.
Common Mistakes
3. to place a letter, number, or symbol on an object so that people can quickly rec
to place a letter, number, or symbol on an object so that people can quickly recognize its category, origin, or destination
Each blood sample was coded with a unique number before being sent to the laboratory.
passive: was coded with — frequently used in passive
The librarian coded every book by subject so that readers could find them more easily.
code + by — organize using a classification system
Museum artefacts are coded with small tags that contain their full catalog history.
The factory worker coded each product with a batch number for safety tracking.
All survey answers were coded according to the age group of each participant.
code + according to — classify based on a criterion
- code + with
- code + by
- code + according to
- coded sample
- coded response
Grammar Patterns
code + noun phrase + with + noun phrase
Usage Note
Distinguish from sense 1 (HIDE MESSAGE): this sense is about classifying and organizing, not about secrecy. The marking is meant to be read by anyone who knows the system, not hidden from unauthorized readers.
4. to depict a person or object in a way that hints at a certain quality or class,
to depict a person or object in a way that hints at a certain quality or class, without saying so directly
The politician's speech coded his opponent as being disconnected from ordinary working people.
code + as — suggest a quality indirectly
Luxury advertisements often code their products as symbols of personal success and social status.
The article coded the neighbourhood as unsafe without ever using that exact word directly.
code + as + adjective — imply a characteristic indirectly
By choosing certain background music and lighting, the film coded the villain as dangerous.
The director coded the scientist as foreign by giving him an accent and unfamiliar customs.
- code + as
- coded language
- coded message
- code + adjective
- signal
more general; can be intentional or unintentional
- convey indirectly
more descriptive and clearer for learners
Grammar Patterns
code + noun phrase + as + noun phrase/adjective
Usage Note
This is an abstract, somewhat technical sense used in media studies, sociology, and criticism. Unlike senses 1-3, it does not involve actual symbols or marks — the 'coding' is done through language, imagery, and cultural associations.
Common Mistakes
5. to carry the genetic information that tells a living thing's cells to produce a
to carry the genetic information that tells a living thing's cells to produce a particular substance or develop a specific feature
A specific gene codes for the production of insulin in the human body.
code + for — instruct the production of a substance
The mutated DNA now codes for a protein that is completely different from the healthy version.
Scientists discovered which section of the genome codes for feather colour in parrots.
code + for + trait — determine a physical characteristic
This stretch of genetic material codes for hair texture and the colour of a person's skin.
The research team found the gene that codes for resistance to a deadly rice fungus.
- code for
- gene codes for
- DNA codes for
- coded to produce
Grammar Patterns
code + for + noun phrase
be coded + to-infinitive
Usage Note
Almost always used in scientific contexts with 'for' (codes for a protein / codes for eye colour). The subject is typically a gene, segment of DNA, or the genetic code itself.
Word family
- codingnounB2
- codedadjectiveB2
- codernounB2
- codifyverbC1
- codificationnounC1
- encodernounC1
- decodernounB2
- decodeverbB2
Synonym discussion
Sense: noun/1
Code and cipher are often used interchangeably in everyday English, but a 'code' replaces whole words or phrases with other words or symbols (e.g., 'Alpha' means 'A'), while a 'cipher' transforms messages letter by letter using an algorithm. 'Symbol system' is a much broader term that covers any set of symbols with agreed-upon meanings, such as traffic signs or musical notation — it does not carry the secrecy aspect that 'code' implies. 'Encoding' refers to the process of converting information from one form to another, which can be either secret or non-secret (for example, encoding audio into MP3 format). 'Cryptography' is the formal academic and technical field of designing secure communication systems. In practical use: 'The children invented their own code for passing notes in class' suggests a simple word-substitution system, whereas 'The mathematician developed a new cipher for military communications' implies a complex letter-level transformation.
Common collocations
Nouns
- code of conduct
- code of practice
- code of honour
- source code
- genetic code
- dress code
- bar code
- area code
- postal code
- penal code
- tax code
- building code
Adverbs
- secretly coded
- genetically coded
- digitally coded
- carefully coded
- specially coded
Phrases
- in code
- break a code
- crack a code
- write code
- lines of code
- code of behaviour
- code of ethics
Prepositions
- code for
- code into
- code as
- code by
- code in
- code with
Etymology
The word 'code' entered English from French 'code' (meaning a set of laws), which came from Latin 'codex' — a book made of wooden writing tablets, later any legal text. The original Latin 'caudex' referred to a tree trunk or block of wood, which ancient Romans split into flat sheets for writing. Over centuries the meaning expanded: first from 'book of laws' to 'any system of rules' (18th century), then to 'a system of secret signals' (19th century, especially in military and telegraphy). The computing sense emerged in the 1940s-50s with the development of stored-program computers, and the genetic sense followed as biologists began to describe DNA's instructions as a 'code' in the 1960s.