What does BID OFF mean?

BID OFF meaning in Law Dictionary

you're believed to "bid down" anything when he bids for it at an auction purchase, which is knocked-down to him in immediate succession on quote so when due to it. Eppes v. Railroad Co., 35 Ala. 56: Doudna v. Harlan, 45 Kan. 484, 25 Pac. 883.