function definition
nounUK /ˈfʌŋkʃən ˌdɛfɪˈnɪʃən/
US /ˈfʌŋkʃən ˌdɛfəˈnɪʃən/
A function definition is the part of a computer program that tells the computer what a function does.
The programmer wrote a function definition that adds two numbers together.
OTHER MEANINGS
2. In mathematics, a function definition states the rule that pairs each input with exactly one output.
The function definition f(x) = x + 2 means every input gets two added to it.
3. A clear explanation of what a particular job or role involves.
The manager wrote a function definition for the new assistant position.
4. The act of explaining the purpose or role of something.
Her function definition of the heart helped the class understand its job.