P.O.

from WordNet (r) 3.0 (2006)

P.O.
    n 1: a noncommissioned officer in the Navy or Coast Guard with a
         rank comparable to sergeant in the Army [syn: {petty
         officer}, {PO}, {P.O.}]

from The Collaborative International Dictionary of English v.0.48

Phosphoryl \Phos"phor*yl\ (f[o^]s"f[o^]r*[i^]l), n. [Phosphorus
   + -yl.] (Chem.)
   The radical {PO}, regarded as the typical nucleus of certain
   compounds.
   [1913 Webster]

from V.E.R.A. -- Virtual Entity of Relevant Acronyms (June 2006)

PO
       Portable Object (MO)

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