sextic
/ˈsɛkstɪk/Mathematics
adjective
Of the sixth degree or order; involving the sixth but no higher power of an unknown quantity or a variable.
noun
An expression, equation, curve, or surface of the sixth degree.
Origin
Mid 19th century; earliest use found in James Joseph Sylvester (1814–1897), mathematician. From classical Latin sextus sixth + -ic. With use as adjective compare quintic. With use as noun compare slightly earlier quintic, quartic, and also octavic.