Semantics is about meaning. It includes:
- the static semantics, which is the part that can be ascertained at compile time, including data typing, whether all variables are declared, which declaration applies to which variable in the case of scoping, what their type is, whether functions and methods are called with correct calling sequences, whether assignments are type-compatible, etc., and
- dynamic semantics, which is what actually happens when the program is executed.
Source: Frank de Remer, Compiler Construction course, University of California, Santz Cruz, 1979.