Why does #define not require a semicolon?

Question

I was writing some test code in C. By mistake I had inserted a ; after a #define, which gave me errors. Why is a semicolon not req

Answer 1

define is a preprocessor directive, and is a simple replacement, it is not a declaration.

BTW, as a replacement it may contain some ; as part of it:

// Ugly as hell, but valid 
#define END_STATEMENT ;

int a = 1 END_STATEMENT // preprocessed to -> int a = 1;