Definition of trigon in US English:



  • 1

    archaic term for triangle
    • ‘This is not easy for me to contemplate and has troubled me for many years - I recall my reluctance to accept the theory that some trigons on a diamond octahedron were produced by dissolution.’
    • ‘It is therefore not enough to count trigons by signs or to expect a true square from signs at intervals at four’.’
    • ‘You can also have a cylinder cone roof wedge trigon prism.’
    1. 1.1 An ancient triangular lyre or harp.
      • ‘Hence, the early Christians were unwilling to bend the knee when they heard the sound of the horn, pipe, lyre, trigon, harp, drum, and entire musical ensemble.’
      • ‘When you hear the sound of the horn, the pipe, the lyre, the trigon and drum and all the musical instruments, you are commanded to bow down and worship.’
    2. 1.2 A triangular cutting region formed by three cusps on an upper molar tooth.
      • ‘The trigon + talon basin forms a broad, shallow depression, bordered posterolingually by the postprotocone fold + postcingulum and covered by crenulated enamel; no postprotocrista or hypocone is evident.’
      • ‘The basic triangular units with three cusps are the trigon and trigonid.’
      • ‘The enamel is extensively crenulated and the postprotocrista low and subdivided so that the trigon and talon basins are nearly confluent, as in P. canpacius.’
      • ‘As the trigon and trigonid meet, they slide past one another, shearing the food item on the edges of the molars as shown.’
      • ‘The preprotocrista is weak and the postprotocrista absent; the trigon and talon basins are fully confluent.’


Early 17th century (in the sense ‘triangle’): via Latin from Greek trigōnon, neuter of trigōnos ‘three-cornered’.