roar of laughter; burst of laughter
Describes a situation where many people laugh at once, creating a lively, swirling atmosphere. Often used in phrases like 笑いの渦に包まれる or 笑いの渦が起こる.
The venue was engulfed in a roar of laughter.
His joke sent the classroom into a burst of laughter.
Compound of 笑い (laughter) and 渦 (whirlpool), metaphorically describing laughter swirling around like a whirlpool.