The word for today is SEMANTICS – which comes from the Greek and then, later on from the Latin – SEMA – meaning SIGN or SYMBOL. It is the study or science of meaning in language.
It is visual information as in the word – SEMAPHORE – which has the Greek root – PHORE – meaning – TO BEAR or TO CARRY at the end of the word.
You may recollect the scenes from naval battles where the shipman is signaling other ships using two flags that are held one in each hand using an alphabetic code based on the position of the signaler’s arms. Signaling is also done with lights or mechanically moving arms.
The science of semantics is enormous because it deals with the historical and psychological study and the classification of changes in the signification of words or forms viewed as factors in linguistic development.
Study the obvious example of the statement: Clark Kent walks into the telephone booth and Superman comes out.
Or, the phrase: truth in fiction. Semantics plays a great role in advertising and in the computer world.