arrears (n.) Look up arrears at
"balance due," early 15c., plural noun from Middle English arrere (adv.) "in or to the rear; in the past; at a disadvantage" (c. 1300), from Anglo-French arrere, Old French ariere "behind, backward," from Vulgar Latin *ad retro, from Latin ad "to" (see ad-) + retro "behind" (see retro-). Arrearage (early 14c.) was the earlier noun. Phrase in arrears first recorded 1610s, but in arrearages is from late 14c.