The Collaborative International Dictionary of English v.0.48:

Aria \A"ri*a\, n. [It., fr. L. a["e]r. See Air.] (Mus.)
   An air or song; a melody; a tune.
   [1913 Webster]

   Note: The Italian term is now mostly used for the more
         elaborate accompanied melodies sung by a single voice,
         in operas, oratorios, cantatas, anthems, etc., and not
         so much for simple airs or tunes.
         [1913 Webster]

WordNet (r) 3.0 (2006):

aria
    n 1: an elaborate song for solo voice

Moby Thesaurus II by Grady Ward, 1.0:

36 Moby Thesaurus words for "aria":
   air, aria buffa, aria cantabile, aria da capo, aria da chiesa,
   aria di bravura, aria di coloratura, aria fugata, aria parlante,
   arietta, arioso, bravura, cantabile, canto, cantus, coloratura,
   descant, ditty, hymn, lay, lied, line, measure, melodia,
   melodic line, melody, note, recitative, refrain, solo, solo part,
   song, soprano part, strain, treble, tune



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

ARIA
       Accessible Rich Internet Applications (W3C, WAI)