See observance in Webster's New World Roget's A-Z Thesaurus II
An act of willingly carrying out the wishes of others:
compliance, obedience. See resistThe act of observing a day or an event with ceremonies:
celebration, commemoration. See rememberA formal act or set of acts prescribed by ritual:
ceremonial, ceremony, liturgy, office, rite, ritual, service. See ritualThe act of noting, observing, or taking into account:
attention, cognizance, espial, heed, mark, note, notice, observation, regard, remark. See knowledge, seeThe act of observing, often for an extended time:
observation, scrutiny, watch. See awareness, seeLearn more about observance