Bullseye

2-2-075

A circular lens (in sense 1 of 2-2-010), or part thereof, usually plano-convex or double convex in section, the optical axis (2-2-110) of which coincides with the optical axis of the prismatic lens of which it forms a part.

Please note that this is the term as it stands in the original IALA Dictionary edition (1970-1989)

English