usual:  That which is usual is etymologically that which is commonly ‘used’ or employed, or which commonly obtains. The word was acquired, probably via Old French usual, from late Latin ūsuālis, a derivative of Latin ūsus (source of the English noun use). => use
late 14c., from Old French usuel "current, in currency (of money), valid" (13c.) and directly from Late Latin usualis "ordinary," from Latin usus "custom" (see use (v.)). The usual suspects is from a line delivered by Claude Rains (as a French police inspector) in "Casablanca" (1942).