# Definition of semicircle in US English:

## semicircle

### noun

• 1A half of a circle or of its circumference.

• ‘Each half consisted of a line that was a semicircle.’
• ‘In other words, a semicircle and a family of abutting semicircles constructed on its diameter are isoperimetric.’
• ‘The crown was crafted out of platinum and designed as three semicircles, one in the center and one on each side.’
• ‘This he affected by circumscribing a semicircle about an isosceles right-angled triangle and a segment of a circle similar to those cut off by the sides.’
• ‘A stationary front is denoted by semicircles and triangles on alternate sides of the front.’
• ‘Throughout the building, circles and semicircles mix with straight lines.’
• ‘His method uses a semicircle rotating in three dimensional space and the curve formed by it cutting another three dimensional surface.’
• ‘His point is well taken, for if circles were defined in terms of semicircles, then presumably semicircles would be defined in terms of the quarter-circles of which they are composed, and so on, ad infinitum.’
• ‘It is two unequal semicircles (with diameters AB and BC) stuck together along their diameters.’
• ‘It appears in all the canvases and works on paper in different combinations and permutations, linked by linear extensions that form varying kinds of S-curves or semicircles.’
• ‘It is well burnished only on the exterior body, which is decorated with a series of engraved ticked circles and semicircles.’
• ‘To the left of the ‘dagger’ a black triangle is gently crowned by a semicircle, gloomily dark gray.’
• ‘Just beyond their embrace, their handlers pawed the ground, growling and barking on their hands and knees, held at bay by double semicircles etched in the dirt that demarcated their sides.’
• ‘They usually exhibit a cross section of roughly a semicircle.’
• ‘Taki - she hasn't gotten his last name and probably never will - has big dark semicircles of anxiety sweat under the arms of his button-down shirt.’
• ‘The solution, a semicircle whose diameter is on the given line, is obtained by reflecting the curve in the line and invoking the isoperimetric property of the circle.’
• ‘In the 70°C samples, semicircles and sinusoidal bends are observed.’
• ‘It is a complete circle and then down on the bottom half there is a semicircle with a little circle above it.’
• ‘The semicircles were made with a sweep of watercolor consisting of Reid's usual diluted mix of red, yellow and blue - a blend that resolves as gray.’
• ‘The most ornamental part of doors was their heads, which took on various shapes, including triangles, semicircles or arcs.’
curve, bow, bend, arc, sweep
View synonyms
1. 1.1 A set of objects arranged in a semicircle.
‘chairs were in a semicircle around the hearth’
• ‘Color-coded control buttons are arranged in a semicircle within thumb's reach for easy, one-hand operation.’
• ‘The patara ruin has rows of stone seats arranged in a semicircle, like the chambers of the American Congress.’
• ‘Tables have been arranged in a semicircle around the bench rather than in the normal linear fashion.’
• ‘Without thinking about it Clara, Tennyson, Cane and Brian had arranged themselves in a semicircle around Nicholas.’
• ‘I'm sat in one of those chairs with a little side table to rest your notebook on, arranged in a semicircle in a darkened room.’

### Origin

Early 16th century: from Latin semicirculus (see semi-, circle).