An Etymological Dictionary of Astronomy and Astrophysics
English-French-Persian

1) The act or process of establishing some value or condition with precision.
2) The formal statement of the meaning or significance of a word, concept, etc.
3) Optics: The clarity, fidelity, sharpness, and brilliancy of an image formed by an optical system.

Verbal noun of → define.

Math.: A definition of a function from which values of the same function can be calculated in a finite number of steps. In mathematical logic and computer science, a recursive definition is used to define an object in terms of itself. An example is the → factorial: n! = n*(n-1)!

→ recursive; → definition.