Lexical semantics is the study of word meaning. It aims to represent the meaning of individual words and morphemes, as well as how word meanings relate to each other. Words are the basic meaningful units of language and have both lexical and grammatical meaning. Below the word level, morphology studies morphemes, the smallest meaningful units that make up words. Word formation processes like inflection, derivation, compounding, and conversion create new words and shift word classes. The meaning of words is also defined by their relationships with other words.