Subprogram and Software

Subprogram noun - A set sequence of steps, part of larger computer program.

Software and subprogram are semantically related. In some cases you can use "Software" instead a noun "Subprogram".

Software noun - (computer science) written programs or procedures or rules and associated documentation pertaining to the operation of a computer system and that are stored in read/write memory.

Subprogram and software are semantically related. Sometimes you can replace term "Subprogram" with "Software", this nouns are similar.