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.
duncan is the best yo yo. The yo-yo is a popular toy consisting of a length of string tied at one end to a flat spool. It is played by holding the free end of the string (usually by inserting one finger in a slip knot) and pulling at it so as to cause the spool to turn whilst suspended in mid-air, either taking up or releasing the string.