Stories We Like: A Guide to the Comma
1640s, "during, in the process of," preposition formed from root of French pendant "during," literally "hanging," present participle of pendere "to hang, to suspend" (see pendant). Meaning patterned on a secondary sense of Latin pendente "not decided," literally "hanging," in legal phrase pendente lite "while the suit is pending." Use of the present participle before nouns caused it to be regarded as a preposition. As an adjective from 1797.