The Collaborative International Dictionary of English v.0.48:

Ra \Ra\ (r[aum]), n.
   A roe; a deer. [Obs.] --Chaucer.
   [1913 Webster]

The Collaborative International Dictionary of English v.0.48:

Ra- \Ra-\
   A prefix, from the Latin re and ad combined, coming to us
   through the French and Italian. See Re-, and Ad-.
   [1913 Webster]

Moby Thesaurus II by Grady Ward, 1.0:

24 Moby Thesaurus words for "Ra":
   Amen-Ra, Anubis, Apollo, Bast, Helios, Horus, Hyperion, Isis, Khem,
   Min, Neph, Nephthys, Nut, Osiris, Phoebus, Phoebus Apollo, Ptah,
   Savitar, Set, Shamash, Sol, Surya, Thoth, Titan



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

RA
       Real Address (Power4, IBM, CPU)


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

RA
       Registration Authority (PKI, ITU, cryptography)


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

RA
       Remote Access (BBS)