A symbol e.g. "record" "end" followed by a colon ":" makes a label.
Labels are used in switch statements and (more rarely) goto statements.
"record" and "end" might be defined in an enum statement.
This is all pretty fundamental C, which will be covered in all good books on the C programming language.
My favourite is "The C Programming Language" by Kernighan and Ritchie.
Hope this helps,
Danish
