The Collaborative International Dictionary of English v.0.48:

Re \Re\ (r[=a]). [It.] (Mus.)
   A syllable applied in solmization to the second tone of the
   diatonic scale of C; in the American system, to the second
   tone of any diatonic scale.
   [1913 Webster]

The Collaborative International Dictionary of English v.0.48:

Re- \Re-\ (r[=e]-). [L. re-, older form (retained before vowels)
   red-: cf. F. re-, r['e]-.]
   A prefix signifying back, against, again, anew; as, recline,
   to lean back; recall, to call back; recede; remove; reclaim,
   to call out against; repugn, to fight against; recognition, a
   knowing again; rejoin, to join again; reiterate; reassure.
   Combinations containing the prefix re- are readily formed,
   and are for the most part of obvious signification.
   [1913 Webster]

   Note: With the increase of electronic connunications, in
         which the vowels with a diaeresis (e.g. ["e]) are
         seldom used in contrast with printed materials, some
         words with re followed by a vowel are now spelled with
         a hyphen to indicate that the two vowels are to be
         pronounced as two syllables rather than as one
         syllable, as in re-emerge rather than re["e]merge. The
         unbroken forms (e.g. reemerge) are, however, usually
         more commonly used, and the pronunciation with two
         syllables for the two vowels is taken as understood.
         [PJC]