depositDefine deposit. deposit synonyms, deposit pronunciation, deposit translation, English dictionary definition of deposit. v. de·pos·it·ed , de·pos·it·ing , de·pos·its v. tr. 1. To put or set down;The car costs $50 per day in rental, plus a $200 deposit which you will get back at the end of the week. You'll get back your deposit once we've checked the bikes are all rht. If furniture is