Lexicology

•   Lexicology investigates the internal structure of the lexicon. Lexicography concerns the compilation of dictionaries. Etymology is about the historical development of word meanings.

•   A lexeme is the minimal distinctive unit in the semantic system of a language. A lexical set is a group of forms which share a basic meaning. A lexical gap is a missing item in a language's lexicon and lexical selection concerns what words can combine with what others, e.g. what nouns are permissible with what verbs.

•   A word field is a collection of words which are related by a common core of meaning, such as furniture, plants, colours, the instruments of an orchestra or whatever.