[de.cade] n [ME, fr. MF decade, fr. LL decad-, decas, fr. Gk dekad-, dekas, fr. deka] (15c) 1: a group or set of 10: as a: a period of
10. years b: a division of the rosary that consists primarily of
10. Hail Marys
2: a ratio of
10. to 1: order of magnitude -- de.cad.al adj