form a friendship with someone

his sister chummed up with Sally

a close friend

she shared the cake with her chums

an old school chum

used as a friendly or familiar form of address between men or boys

it's your own fault, chum

fish using chum as bait

chumming is always a must when flounder fishing

chopped fish and other material thrown overboard as angling bait

the anglers anchored down and put out their blood chum

a large North Pacific salmon that is commercially important as a food fish