late 13c., "honor, respect, deference (shown to someone), esteem heightened by awe," also of places or holy objects, from Old French reverence "respect, awe" and directly from Latin reverentia "awe, respect," from revereri "to stand in awe of, respect, honor, fear, be afraid of; revere," from re-, here perhaps an intensive prefix (see re-), + vereri "stand in awe of, fear, respect" (from PIE root *wer- (3) "perceive, watch out for").
Reverence is nearly equivalent to veneration, but expresses something less of the same emotion. It differs from awe in that it is not akin to the feeling of fear, dread, or terror, while also implying a certain amount of love or affection. We feel reverence for a parent and for an upright magistrate, but we stand in awe of a tyrant. [Century Dictionary]
From late 14c. as "state of being revered or venerated." As a respectful form of address, with possessive pronoun, to a clergyman or ecclesiastic, late 14c. (Gower), "latterly only used by the lower classes, esp. in Ireland" [OED].