- (uncountable) The state of being happy or merry.
- 1963, Margery Allingham, chapter 2, in The China Governess:
- Now that she had rested and had fed from the luncheon tray Mrs. Broome had just removed, she had reverted to her normal gaiety. She looked cool in a grey tailored cotton dress with a terracotta scarf and shoes and her hair a black silk helmet.
- There was much gaiety at the ball.
- The decorations added greatly to the gaiety of the room.
- (countable) Merrymaking or festivity.
- (state of being happy): gayness