Answer: thewave

AnswerCrossword Clue
THEWAVE

Undulating fans

THEWAVE

It's caused by standing fans

THEWAVE

Coordinated fan effort at a stadium

THEWAVE
Up-and-down fan fun
THEWAVE
What oscillating fans do
THEWAVEMotion made by fans in a stadium
THEWAVEStand-up routine?
THEWAVEStand-up routine in a stadium?
THEWAVEThousands of fans might do it
THEWAVEMotion of fans in a stadium
THEWAVECrowd activity at a stadium