very important in understanding or describing something: 2. (of a clause) giving information…. DEFINING definition: decisive ; critically important | Meaning, pronunciation, translations and examples To state the precise meaning of (a word or sense of a word, for example). To describe the nature or basic qualities of; explain: define the properties of a new drug; a study that defines people according … Definition of defining adjective in Oxford Advanced Learner's Dictionary. Meaning, pronunciation, picture, example sentences, grammar, usage notes, synonyms and more. to state or set forth the meaning of (a word, phrase, etc.): They disagreed on how to define "liberal.'' describe: to define judicial functions. specify distinctly: to define one's responsibilities. to determine or … defining definition: serving to establish the nature of something. Check meanings, examples, usage tips, pronunciation, domains, and related words. Discover expressions like "defining moment", "defining … Defining refers to the act of stating the exact meaning of a word or phrase, or establishing the essential qualities of something. It is often used in contexts such as language, philosophy, or science to clarify … defining, n. meanings, etymology, pronunciation and more in the Oxford English Dictionary.