Mathematical function; a relation between a set of inputs and a set of permissible outputs.
I defined a function y = x².
Please draw the graph of this function.
Quadratic functions are learned in junior high school.
In programming, a named section of a program that performs a specific task.
This function takes two arguments.
An error occurred, so please review the function definition.
Find the value of the function when x = 2.
Let's try graphing this function.
This program calls this function every second.
Passing a string to this function causes an error.
This function returns a boolean value.
変数 (variable) and 関数 (function) both end in 数 and appear together in math/programming, but a variable holds a value while a function defines a relationship between inputs and outputs.
係数 (coefficient) shares the ending 数 with 関数 and appears in the same equations, but a coefficient is a fixed multiplying number, not a function itself.
関数 is counted with 個, as in 二つの関数 (two functions), the generic counter for abstract or discrete items.
Standard modern kanji form.
Rarely used older kanji form; 関数 is preferred in modern writing.
From Chinese 函數／函数 (hánshù), literally 'box number', a calque of English 'function'. The kanji 関 (connection) replaced 函 (box) in modern Japanese usage.
inverse function