1) Function 2) Package 3) Procedure 4) Routine 5) Software 6) Software package 7) Software system 8) Subprogram 1) Subprogram 
In computer programming, a subroutine is a sequence of program instructions that perform a specific task, packaged as a unit. This unit can then be used in programs wherever that particular task should be performed. Subprograms may be defined within programs, or separately in libraries that can be used by multiple programs. In different programmin...
a sequenced set of statements that may be used in one or more programs and at one or more points in a program
an instruction sequence in a machine or assembly language program that can be prewritten and referred to as often as needed. Cf.(def. 4a).