Video shows what yo-yo means. A toy consisting of a spheroidal or cylindrical spindle having a circular groove in which string is wound; it is used by holding the string in the fingers and reeling the spindle up and down by movements of the wrist.. A volatile market that moves up and down.. Someone who vacillates.. Yo-yo Meaning. How to pronounce, definition audio dictionary. How to say yo-yo. Powered by MaryTTS, Wiktionary