A simile (/ˈsɪməli/) is a figure of speech that directly compares two things. Similes differ from other metaphors by highlighting the similarities between two things using comparison words such as "like", "as", "so", or " than", while other metaphors create an implicit comparison (i.e., saying something "is" something else). This distinction is evident in the etymology of the words: simile derives from the Latin word similis ("similar, like"), while metaphor derives from the Greek word metapherein ("to transfer").
In linguistics, the grammar of a natural language is its set of structural constraints on speakers 'or writers' composition of clauses, phrases, and words. The term can also refer to the study of such constraints, a field that includes domains such as phonology, morphology, and syntax, often complemented by phonetics, semantics, and pragmatics. There are currently two different approaches to the study of grammar, traditional grammar and theoretical grammar.