Function (mathematics)

Method (computer programming)

Command–query separation (CQS)

Coroutines, subprograms that call each other as if both were the main programs

Event handler, a subprogram that is called in response to an input event or interrupt

Asynchronous procedure call, a subprogram that is called after its parameters are set by other activities

image subroutine

define subroutine

wikipedia subroutine

weblio subroutine

kotobank subroutine

jisho subroutine