The adjective ancillary originally meant "relating to maidservants" from the Latin, but the element of a female servant has fallen away and now the word merely refers to a position as helpful or subordinate.
Incorporeal comes from a combination of the Latin root words in- meaning "not" and corpus meaning "body." Combined they form incorporeus, meaning "without body," which is precisely what something incorporeal is
Circum in Latin means "around" or "round about," and vent- comes from venire, "to come," but painting a picture from these two parts of the word helps.
The word comes from the Latin roots com- meaning "together" and terere which means "to rub." It's also related to the Latin word conterere and is defined as "to bruise."