Longman Dictionary of Contemporary English - balloon

~1 n 1 a small brightly coloured rubber bag that can be filled with air and used as a toy or decoration for parties 2 a large bag of strong light cloth filled with gas or heated air so that it can float in the air  (hot air balloons drifting toward the horizon) 3 the circle drawn around the words spoken by the characters in a cartoon 4 balloon payment AmE money borrowed that must be paid back in one large sum after several smaller payments have been made  (a $10,000 balloon payment due in two years) 5 go down like a lead balloon informal if a joke, remark etc goes down like a lead balloon, people do not laugh or react as you expected ~2 v 1 to get bigger and rounder + out/outwards/up  (His cheeks ballooned out as he played his trumpet.) 2 to become larger in amount  (Mitch's business debts ballooned to $20,000, in just one year.)