The word cavalcade is a rapidly-declining term meaning "procession of horses". It was borrowed in the 1590s and comes, through Middle and Old French, from the Italian verb cavalcare, which meant "to ride on horseback", and the noun-forming suffix -ade. Cavalcare is from Vulgar Latin caballicare, where the root is caballus, with a definition of "horse". That in turn has a disputed origin, but likely has Proto-Celtic roots, because there are cognates in Irish, Manx, and Welsh. Here it gets interesting! In the early 1910s, Lyle Abbot, the automobile editor of the Arizona Republican, had a need to refer to a procession of automobiles, so he created the word motorcade, under the assumption that -cade was the suffix in cavalcade. It, of course, was not, but by now it's far too late to change that and we're stuck with an errant c in motorcade for eternity.
Adam Aleksic, a rising sophomore studying linguistics and government at Harvard University, has been described as the internet's sixth most famous etymologist. He also has disturbing interests in politics, vexillology, geography, board games, conlanging, and law.