quartic Syllabification: (quar·tic)Pronunciation: /ˈkwôrtik/ MathematicsDefinition of quartic adjective involving the fourth and no higher power of an unknown quantity or variable. noun a quartic equation, function, curve, or surface. Origin: mid 19th century: from Latin quartus 'fourth' + -icquartic in other Oxford dictionaries Definition of quartic in the British & World English dictionary