"Semicircular" refers to something that is shaped like half of a circle. It means that an object or a line has a curved shape that resembles half of a round circle or a half-moon shape. Full definition
Using a vegetable - bristle dry brush, brush gently up and toward the heart in semicircular motions, just until the skin becomes slightly red. (mindbodygreen.com)
Also known as scissor trimmers, this type is called as such because it looks like scissors, but with semicircular indentions on the blade. (puphow.com)
Since medieval times, players of double - reed instruments in the oboe, bassoon, shawm, dolcian, and chanter family have used a small, thin, usually arrow - shaped or semicircular piece of metal, now usually plastic or wood, to help scrape and shape the cane used to construct the reed. (discovermagazine.com)