Grammar is the set of rules that govern how we use language. It includes both the spoken and written word and is concerned with adequately using words, phrases, clauses, and sentences. Grammar can be divided into two main categories: syntax and morphology. Syntax deals with how words are combined to form phrases and sentences, while morphology deals with the internal structure of words themselves.
While some people might view grammar as nothing more than a set of stuffy rules to be followed, it plays an essential role in our lives. For one thing, it helps us communicate effectively by ensuring that others understand our messages clearly and easily. Also, grammar allows us to create a positive impression when we speak or write; proper grammar is often seen as a sign of intelligence and education level.
See Dictionary and Thesaurus