扇形

shànxíng
circular sector

CEDICT

  1. (geometry) circular sector (shape)
  2. circular sector (shape)

Wiktionary

以圓的兩半徑及其所截的弧圍成的部分，稱為「扇形」。此扇形通常小於半圓。

重編國語辭典

Entry Composition

1 扇 shàn
  1. fan
  2. sliding, hinged or detachable flat part of sth
  3. classifier for doors, windows etc
2 形 xíng
  1. to appear
  2. to look
  3. form
  4. shape