Sĕnĕcĭo, ōnis, m. [senex],
a Roman surname , Tac. Agr. 2; 45; id. A. 13, 12; 15, 50; 15, 56 sq.; Plin. Ep. 3, 11, 3.
·noun A very large genus of composite plants including the groundsel and the golden ragwort. ...
Webster's Dictionary of the English Language