An`a*clas"tic (&?;), a. [Gr. &?; to bend back and break; to reflect (light); &?; + &?; to break.] 1. (Opt.) Produced by the refraction of light, as seen through water; as, anaclastic curves.

2. Springing back, as the bottom of an anaclastic glass.

Anaclastic glass, a glass or phial, shaped like an inverted funnel, and with a very thin convex bottom. By sucking out a little air, the bottom springs into a concave form with a smart crack; and by breathing or blowing gently into the orifice, the bottom, with a like noise, springs into its former convex form.