tri ‧ an ‧ gle /ˈtraɪæŋɡ ə l/ BrE AmE noun [countable]
[ Date: 1300-1400 ; Language: Latin ; Origin: triangulum , from tri- ( ⇨ ↑ tri- ) + angulus 'angle' ]
1 . a flat shape with three straight sides and three angles
2 . something that is shaped like a triangle:
a triangle of land
3 . a musical instrument made of metal bent into the shape of a triangle. You hit it with a metal stick to make a ringing sound.
4 . American English a flat plastic object with three sides that has one angle of 90° and is used for drawing angles SYN set-square British English
• • •
THESAURUS
■ types of shapes
▪ square a shape with four straight sides that are equal in length and four angles of 90 degrees
▪ circle a round shape that is like an O
▪ semicircle half a circle
▪ triangle a shape with three straight sides and three angles
▪ rectangle a shape with four straight sides and four angles of 90 degrees
▪ oval a shape like a circle, but that is longer than it is wide
▪ cylinder an object in the shape of a tube
▪ cube a solid object with six equal square sides
▪ pyramid a shape with a square base and four triangular sides that meet in a point at the top
▪ sphere a shape like a ball