It is sometimes compared with syntax, which concerns the rules that dictate how sentences are formed.
Example
Semantic change is when a word changes meaning. It can become wider in meaning or narrower, or more positive or more negative. An example is the word 'bad', which has changed meaning from negative to positive in some contexts.
In the classroom
Semantic areas looked at in language learning in addition to the simple study of meaning include discourse analysis, word groups such as homonyms, synonyms and antonyms, and compound structures.
Further links:
https://www.teachingenglish.org.uk/article/presenting-vocabulary
https://www.teachingenglish.org.uk/article/vocabulary-autonomy
https://www.teachingenglish.org.uk/article/teacher-talk-building-retaining-vocabulary
https://www.teachingenglish.org.uk/article/working-vocabulary
https://www.teachingenglish.org.uk/article/same-opposite-or-different-dictation