means A heartfelt address or petition to a god or higher power, whether asking for something, giving thanks, or simply opening a line of spiritual communication.

from From Latin precari, "to beg, entreat," rooted in prex, "a request." It traveled through Old French preiere into Middle English as preiere, the act of asking made sacred. That same Latin precari is the buried ancestor of "precarious" — a thing so uncertain you could only pray for it — and of "deprecate," to pray something away.