Physics, Chemistry. 1  a wave function describing the state of a single electron in an atom (atomic orbital) or in a molecule (molecular orbital) 2  the electron in that state.
DEFINITION of 'Yo-Yo'. Slang for a very volatile market. A yo-yo market will have no distinguishing features of either an up or down market, taking on characterstics of both. Security prices in a yo-yo market will swing very high to low over a given period of time, making it difficult for buy and hold investors to profit. Next Up.
YOI is the acronym for the ice skating anime, Yuri!!! On Ice. It tells the story of the career of a competitive ice skater, Yuuri Katsuki, and his attempt to redeem himself from previous his failures. All while dealing with budding relationship between him and his coach Viktor Nikirov.