1. The act of determining or making something distinct, or clear: The geology professor provided the definitions of several terms referring to the same kind of rock formations.
2. The formal statement of the meaning or significance of a word, phrase, or term, as in a dictionary entry: After reading the article in the newspaper, Carol looked up the definition of "palindrome" in the on-line dictionary.
3. A condition of being distinct, or clearly outlined: The negotiators were clear as to the definitions of overtime to include in the new union contract.
4. The act or process of stating a precise meaning or significance; formulation of a meaning: Karen was asked to provide a definition of the terms she was using in her speech at the City Hall.
5. In optics, the sharpness of the image formed by an optical system: Tom was very pleased with the high definition that was available in his new camera.
6. In radio and television, the accuracy of sound or picture reproduction: Lisa adjusted the definition of the picture in her new TV set.