喜樂美語
  1. 1凹的、凹面的（和凸面 convex 相對）

    A concave surface curves in the middle, like the inside of a bowl or a spoon. Light in a concave mirror or lens is gathered inward. The everyday partner word is convex, which bulges out. You use concave in maths, science, and careful talk about shape — bowls, dishes, some lenses, the inner side of a curve. Though actually, people sometimes say concave when they only mean “hollow” or “dented,” which is close but looser: a dent is a local knock, while concave is a smooth inward curve. As a noun, the concave can mean that inward-curving side, but the adjective is what you will meet most. A simple memory trick that also fits the history: concave is like a cave — it goes in.

組成From Middle English concave, from Old French concave, from Latin concavus: con- (together / fully) + cavus (“hollow”).

同家族的字

  • caveshares the “hollow” idea from Latin cavus
  • cavitya hollow space, from the same Latin cavus

原始詞典資料12 筆記錄

以下是外部詞典記錄的用法，摘錄並精簡格式，我們還沒有寫成教學內容。上面的說明才是我們自己寫的；有些用法可能上面已經講過了。

concaveadj/ˈkɒn.keɪv/

  • 1

    Curved like the inner surface of a sphere or bowl.

  • 2

    geometrymathematicssciencesNot convex; having at least one internal angle greater than 180 degrees.

  • 3

    Satisfying the property that all segments connecting two points on the function's graph lie below the function.

  • 4

    Hollow; empty.

    • as concave […] as a worm-eaten nut

concavenoun/ˈkɒn.keɪv/

  • 1

    A concave surface or curve.

  • 2

    The vault of the sky.

  • 3

    One of the celestial spheres of the Ptolemaic or geocentric model of the world.

    • Aristotle makes [Fire] to move to the concave of the Moon. - Thomas Salusbury (1661).
  • 4

    businessmanufacturingAn element of a curved grid used to separate desirable material from tailings or chaff in mining and harvesting.

  • 5

    hobbieslifestylesportsAn indentation running along the base of a surfboard, intended to increase lift.

  • 6

    hobbieslifestyleskateboardingAn indented area on the top of a skateboard, providing a position for foot placement and increasing board strength.

  • 7

    gamblinggamesA playing card made concave for use in cheating.

concaveverb/ˈkɒn.keɪv/

  • 1

    To render concave, or increase the degree of concavity.

摘錄自 英文維基詞典 English Wiktionary，已精簡格式；依 CC BY-SA 4.0 授權使用，改動後的內容同樣以此授權提供。