Anastigmatic \An*as`tig*mat"ic\, a. [Pref. an-not + astigmatic.]

(Optics) Not astigmatic; -- said esp. of a lens system which consists of a converging lens and a diverging lens of equal and opposite astigmatism but different focal lengths, and sensibly free from astigmatism.

Source: Webster's Revised Unabridged Dictionary (1913)