The Collaborative International Dictionary of English v.0.48:

Phonetics \Pho*net"ics\ (f[-o]*n[e^]t"[i^]ks), n.
   1. The doctrine or science of sounds; especially those of the
      human voice; phonology.
      [1913 Webster]

   2. The art of representing vocal sounds by signs and written
      characters.
      [1913 Webster]

WordNet (r) 3.0 (2006):

phonetics
    n 1: the branch of acoustics concerned with speech processes
         including its production and perception and acoustic
         analysis

Moby Thesaurus II by Grady Ward, 1.0:

62 Moby Thesaurus words for "phonetics":
   ablaut, acoustic phonetics, articulatory phonetics, audiometer,
   auriscope, auriscopy, betacism, bowwow theory, cacography,
   comparative linguistics, derivation, descriptive linguistics,
   dialectology, dingdong theory, etymology, glossematics, glossology,
   glottochronology, glottology, gradation, grammar, graphemics,
   historical linguistics, language study, lexicology,
   lexicostatistics, linguistic geography, linguistic science,
   linguistics, mathematical linguistics, morphology, morphophonemics,
   mutation, orthoepy, orthography, otography, otolaryngology,
   otology, otoneurology, otopathy, otoplasty, otoscope, otoscopy,
   paleography, philology, phonetic spelling, phonography, phonology,
   psycholinguistics, rhotacism, semantics, sociolinguistics,
   sound shift, spelldown, spelling, spelling bee, spelling match,
   spelling reform, structuralism, syntactics,
   transformational linguistics, umlaut