yo-yo Definition

yo-yo
noun yo-yos

1. A toy consisting of a pair of wooden, metal or plastic discs joined at their centre with a deep groove between them, and with a piece of string attached to and wound round the joining axis within the groove, the toy being repeatedly made to unwind from the string by the force of its weight and rewind by its momentum.
2. Someone or something regarded as like a yo-yo in some way, eg because it moves up and down, varies or fluctuates continuously.

verb

intr
yo-yoed, yo-yoing
1. To rise and fall repeatedly; to fluctuate repeatedly in any way.

Etymology: Originally (1915) a trademark: apparently Filipino, applied to a similar device, but literally meaning ‘come come'.