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