Pronunciation: (def"u-nish'un),[key] —n. 1. the act of defining or making definite, distinct, or clear.
2. the formal statement of the meaning or significance of a word, phrase, etc.
3. the condition of being definite, distinct, or clearly outlined.
4. Optics.sharpness of the image formed by an optical system.
5. Radio and Television.the accuracy of sound or picture reproduction.