IPA: /ˈpriːprəʊsɛsər/
KK: /priˈprɒsɛsər/
A program that takes input data, processes it, and produces output that can be used by another program.
The preprocessor converts the source code into a format that the compiler can understand.
Preprocessor → It is formed from "pre-" (meaning before) and "process" (from Latin "processus", meaning a series of actions or steps). The word refers to a program that processes data before the main processing occurs.
Think of something that works 'before' ('pre-') the main 'process' — that's what a preprocessor does.