What is the meaning of semantics?

by Karel Thönissen

Semantics is a branch of semiotics, the study of signs. Other well-known branches are syntactics (the study of form) and pragmatics (the study of intentions of signs, or rather of their utterers). There are four other branches in Stamper's semiotic framework.

What people in computer science commmonly refer to as semantics is not dealing with the meaning of signs, but how a sign (e.g. a computer program or data structure) relates to other computer programs or data structures. For example, two data structures can be semantically equivalent, or a syntactically well-formed program can violate a semantic constraint which makes the program equivalent to the halt-program.

Although this is commonly referred to as semantics, this is in fact a sub-branch of syntactics, named 'formal semantics' (sic). In my research in this area I minted, the term 'formantics' to end this confusion.

However, in some areas of computing people indeed are referring to the meaning of signs by relating them to the outside world. Think of semantic nets and semantic modelling for databases. This is semantics proper.

More on this subject in my blog of 2004.04.23 at http://www.hello.nl/blogs/2004Q2.html.