code
n. C / Un. a set of rules or symbols used to represent information. You use it when you want to send secret messages or when you write instructions for a computer.
n. a system of signals, symbols, or rules used to represent information for communication or processing. Often refers to the instructions written in a programming language or a set of ethical principles.
The programmer writes code for the new app.
The hospital staff uses a special code over the loudspeaker to announce emergencies without alarming the patients.
While the genetic code determines many physical traits, environmental factors play a significant role in how those traits are expressed throughout an individual's life.
From Middle English code (“system of law”), from Old French code (“system of law”), from Latin cōdex, later form of caudex (“the stock or stem of a tree, a board or tablet of wood smeared over with wax, on which the ancients originally wrote; hence, a book, a writing.”). Doublet of codex. Verb etymology 1 sense 7 is an ellipsis of code blue (“medical emergency”).
Uncountable when referring to computer programming instructions in general; countable when referring to a specific system of rules or a secret cipher.
I wrote many codes todayI wrote a lot of code todayWhen referring to computer programming instructions, the word is uncountable and does not take a plural form.