WordNet
concave lens
n. a lens such that a parallel beam of light passing through it is caused to diverge or spread out [syn: diverging lens]
Usage examples of "concave lens".
He flipped up a round concave lens near the head of his walking-stick and invited me to examine my manuscript through it.
If it passes through a convexo-concave lens, it can even be narrowed!
From Darlow, it looked more like a concave lens than a convex one.
He could use a concave lens of air, held in shape by a film of his own flesh, which was far more transparent than an optical system composed entirely of the latter substance.