In linguistics and grammar, a sentence is a linguistic expression such as the English example "The quick brown fox jumps over the lazy dog." In traditional grammar, it is typically defined as a string of words that expresses a complete thought or as a unit consisting of a subject and predicate. In non-functional linguistics, it is typically defined as a maximal unit of syntactic structure such as a constituent. In functional linguistics, it is defined as a unit of written texts delimited by graphological features such as upper case letters and markers such as periods, question marks, and exclamation marks. This notion contrasts with a curve delimited by phonologic features such as pitch and loudness and markers such as pauses, and with a clause, which is a sequence of words that represents some process going on throughout time.
 

English Grammar Terms III

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.