ETYM Latin cavernosus: cf. French caverneux.
Being or suggesting a cavern.
Of a surface, curving inward, or away from the eye. For example, a bowl appears concave when viewed from above. In geometry, a concave polygon is one that has an interior angle greater than 180ş. Concave is the opposite of convex.
ETYM Old Eng. holow, holgh, holf, AS. holh a hollow, hole. Related to Hole.
1. As if echoing in a hollow space.
2. Not solid; having a space or gap or cavity.
In a concave way.
In the manner of being empty inside; meaninglessly; insincerely