noun

• (countable, geometry, rare) A triangle.
• (countable, historical, music) An ancient triangular harp of Oriental origin which had four strings and was often used for banquet music. Also called sabbeka, sackbut, sambuca.
• (countable, astrology) A division consisting of three signs.
• (countable, astrology) A trine; an aspect of two planets distant 120 degrees from each other.
• (uncountable, historical) An old ball game played by three people standing in a triangular formation.
• (countable, zoology) The cutting region of the crown of an upper molar, usually the anterior part.