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.
uk â /ËjÉÊ.jÉÊ/ us â /ËjoÊ.joÊ/ plural yo-yos trademark. âº a toy consisting of a circular object that can be made to go up and down a long piece of string to which it is tied. Thesaurus: synonyms and related words. Toys & dolls. action figure.