01 a. Not astigmatic; free of astigmatism; -- pertaining to a lens or lens system, and used especially of a lens system which consists of a conv…
-
1.
Not astigmatic; free of astigmatism; -- pertaining to a lens or lens system, and used especially 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.(Optics)