sextic

Century Dictionary and Cyclopedia

1. Of the sixth degree; of the sixthorder.
2. n. A quantic, or equation, of the sixth degree; also, a curve of the sixth order

Wiktionary

1. adj. mathematics Of the sixth degree or order.
2. n. mathematics A quantic of the sixth degree.

GNU Webster's 1913

1. adj. (Math.) Of the sixth degree or order.