: name ( ... -- ... )
word1 word2 word3 ;
Creates a word called name that, upon execution, executes
word1 word2 word3. name is a (colon) definition.
The explanation above is somewhat superficial. For simple examples of colon definitions see Your first definition. For an in-depth discussion of some of the issues involved, See Interpretation and Compilation Semantics.
: ( "name" – colon-sys ) core “colon”
; ( compilation colon-sys – ; run-time nest-sys ) core “semicolon”