An Etymological Dictionary of Astronomy and Astrophysics

1. Strictly accurate or correct; precise, as opposed to approximate.
   

2. The complete solution of an equation. For example, in the equation x² = 7, the positive solution 2.646 is correct to three decimal places. The exact answer is x = 7^1/2.
   

See also:
→ exact differential, → exact differential equation, → exact science, → accurate,
→ precise, → rigorous.

Etymology (EN): From L. exactus, p.p. of exigere, literally “to drive out, thrust out,” also “demand, finish, measure,” from → ex- “out”

• agere “drive, lead, act,” → act.

Etymology (PE): Razin “firm, solid, strong” [Dehxodâ, Steingass], Mid.Pers. razên “firm, strong, secure, solid.”