pentagon

pentagon — noun

1. a closed shape made from five straight lines, creating five points

1.名詞B2
釋義

a closed shape made from five straight lines, creating five points

例句

Nina drew a pentagon on the poster with a black marker.

draw a pentagon

The map showed a pentagon beside the square and the triangle.

同義詞
  • polygon

    the general class word; a pentagon is one kind of polygon

  • five-sided figure

    clear descriptive wording, but less standard than the math term

  • shape

    much broader and not limited to figures with straight sides

反義詞
  • triangle

    has three sides instead of five

  • hexagon

    has six sides instead of five

文法句型

draw a pentagon

a regular pentagon

a pentagon with five corners

用法筆記

Usually countable in math and design. Common with words that show shape or drawing, such as regular, draw, corner, and side.

常見錯誤

❌A pentagon has six sides.
✅A pentagon has five sides.
💡the word always refers to a five-sided figure.

2. the large five-sided headquarters near Washington, D.C., and also the American d

2.名詞B2
釋義

the large five-sided headquarters near Washington, D.C., and also the American defense department it stands for in news reports

例句

Reporters waited outside the Pentagon before the news meeting started.

literal place: outside the Pentagon

The Pentagon announced new aid after the storm hit the island.

metonymic use: the department announced something

同義詞

文法句型

the Pentagon announced...

outside the Pentagon

inside the Pentagon

用法筆記

Usually capitalised and used with the. In news writing, it often names the defense department or its leaders, not only the building.

常見錯誤

❌pentagon said the plan was ready.
✅The Pentagon said the plan was ready.
💡this proper noun normally takes a capital P and the article 'the'.