In linguistics, a word of a spoken language can be defined as the smallest sequence of phonemes that can be uttered in isolation with objective or practical meaning. In many languages, words also correspond to sequences of graphemes ("letters") in their standard writing systems that are delimited by spaces wider than the normal inter-letter space or by other graphical conventions. The concept of "word" is usually distinguished from that of a morpheme, the smallest unit of a word that has a meaning, even if it will not stand on its own.
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.