semicircle

(sĕm'ĭ-sûr'kəl)
n.

1. A half of a circle as divided by a diameter.
2. An object or arrangement of objects or people in the shape of half a circle.

semicircular sem'i·cir'cu·lar (-kyə-lər) adj.

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IN BRIEF: Half of a round shape.

She liked that the moon looked like a semicircle.

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Shaped like a half-circle.

• s. canals — the passages in the inner ear, in the bony labyrinth concerned with the sense of balance, especially the detection of movement. Each ear has three semicircular canals (anterior, lateral and posterior) situated approximately at right angles to each other. They contain the semicircular ducts.
• s. ducts — the membranous tubes housed within the semicircular canals.They have enlarged portions at one end, called ampullae, which contain nerve endings, and which are filled with fluid.
— The semicircular ducts respond to movement of the head. When the head changes position, the fluid in the duct that lies in the plane of movement also moves but, because of its inertia, the fluid flow lags behind the head movement. Thus the fluid presses against the delicate hairs of the nerves in the ampulla, and these nerves then register the fact that the head is turning in such a direction. — It is the fluid movement in the semicircular ducts that causes the feeling of dizziness or vertigo after spinning. When the spinning stops, the fluid in the horizontal canal continues to move for a moment in the direction of the spin, giving a temporary false reading that the head is turning in the other direction. Motion sickness is caused by the unusual and erratic motions of the head in an airplane, car or ship, and the resulting stimulation of the semicircular ducts. Many animals, even fish, can experience motion sickness.

For a list of words related to semicircle, see:

• Geometric Shapes and Mathematically Defined Forms - semicircle: half of a circle, formed by arc from one end of diameter to the other
• Shapes - semicircle: half a circle

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See words rhyming with "semicircle."

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Dansk (Danish)
n. - halvcirkel

Nederlands (Dutch)
halve cirkel

Français (French)
n. - demi-cercle

Deutsch (German)
n. - Halbkreis

Ελληνική (Greek)
n. - ημικύκλιο

Italiano (Italian)
semicerchio

Português (Portuguese)
n. - semicírculo (m)

Русский (Russian)
полуокружность, полукруг

Español (Spanish)
n. - semicírculo

Svenska (Swedish)
n. - halvcirkel

中文（简体）(Chinese (Simplified))
半圆, 半圆形, 半圆弧

中文（繁體）(Chinese (Traditional))
n. - 半圓, 半圓形, 半圓弧

한국어 (Korean)
n. - 반원형, 반원형의 것

日本語 (Japanese)
n. - 半円, 半円形, 半円形のもの

العربيه (Arabic)
‏(الاسم) نصف دائرة‏

עברית (Hebrew)
n. - ‮חצי-עיגול, חצי-מעגל‬

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