The Collaborative International Dictionary of English v.0.48:

Vanadyl \Van"a*dyl\, n. [Vanadium + -yl.] (Chem.)
   The hypothetical radical VO, regarded as a characteristic
   residue of certain vanadium compounds.
   [1913 Webster]

V.E.R.A. -- Virtual Entity of Relevant Acronyms (February 2016):

VO
       Virtual Organization (grid)