noun
plural yo-yos
[count] :a round toy that has two flat sides with a string attached to its center, that is held in your hand, and that is made to go up and down by unwinding and rewinding the string with a movement of your wrist
verb
yo-yos; yo-yoed; yo-yoing
[no obj] :to move repeatedly and quickly up and down or from a higher level to a lower level