The Collaborative International Dictionary of English v.0.48:

Piu \Pi"[`u]\, adv. [It., fr. L. plus. See Plus.] (Mus.)
   A little more; as, pi[`u] allegro, a little more briskly.
   [1913 Webster]

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

PIU
       Path Information Unit (IBM, SNA)


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

PIU
       Plug-In Unit