con·cave /kɑnˈkev, ˈkɑnˌ/
  (a.)凹的
  con·cave /kɑnˈkev, ˈkɑnˌ/ 形容詞
  concave
  凹
  concave
  凹
  Con·cave a.
  1. Hollow and curved or rounded; vaulted; -- said of the interior of a curved surface or line, as of the curve of the of the inner surface of an eggshell, in opposition to convex; as, a concave mirror; the concave arch of the sky.
  2. Hollow; void of contents. [R.]
     As concave . . . as a worm-eaten nut.   --Shak.
  Con·cave, n.
  1. A hollow; an arched vault; a cavity; a recess.
     Up to the fiery concave towering hight.   --Milton.
  2. Mech. A curved sheath or breasting for a revolving cylinder or roll.
  Con·cave, v. t. [imp. & p. p. concaved p. pr. & vb. n. Concaving.] To make hollow or concave.
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  concave
       adj : curving inward [ant: convex]