Definition of trisect in English:
trisect
Line breaks: trisectPronunciation: /trʌɪˈsɛkt
/
verb
 Divide (something) into three parts, typically three equal parts: two walls trisect the galleryMore example sentences
 Nicomedes trisected any rectilinear angle by means of the conchoidal curves, of which he had handed down the origin, order, and properties, being himself the discoverer of their special characteristic.
 Today, even as traffic signals multiply and thick yellow lines bisect and trisect the roads, motorists, scooterists and nonconformists all line up together at painfully long red lights and plan strategy.
 The right of the two diagrams shows how this hyperbola can be used to trisect the angle AOB.
Derivatives

trisection
noun
 More example sentences
 He also discussed parabolas, angle trisection and magic squares.
 In extending from the Pythagorean numbers to the totally real Vietens, it is important to understand the constructions involving trisections.
 Three geometric construction problems from antiquity puzzled mathematicians for centuries: the trisection of an angle, squaring the circle, and duplicating the cube.

trisector
noun
 More example sentences
 Their centers thus lie on the trisectors of the angles adjacent to that line.
 If the angles of any triangle be trisected, the triangle, formed by the meets of pairs of trisectors, each pair being adjacent to the same side, is equilateral.
 We no longer look kindly on angle trisectors and circle squarers.
Origin
late 17th century: from tri 'three' + Latin sect 'divided, cut' (from the verb secare).