The Collaborative International Dictionary of English v.0.48:

Tonality \To*nal"i*ty\, n. [Cf. F. tonalit['e].] (Mus.)
   The principle of key in music; the character which a
   composition has by virtue of the key in which it is written,
   or through the family relationship of all its tones and
   chords to the keynote, or tonic, of the whole.
   [1913 Webster]

         The predominance of the tonic as the link which
         connects all the tones of a piece, we may, with
         F['e]tis, term the principle of tonality. --Helmholtz.
   [1913 Webster]

WordNet (r) 3.0 (2006):

tonality
    n 1: any of 24 major or minor diatonic scales that provide the
         tonal framework for a piece of music [syn: key,
         tonality] [ant: atonalism, atonality]

Moby Thesaurus II by Grady Ward, 1.0:

72 Moby Thesaurus words for "tonality":
   French pitch, Klangfarbe, arc lighting, black and white,
   chiaroscuro, clang color, classical pitch, color, coloring,
   contrast, decorative lighting, depth, direct lighting, dominant,
   dulcetness, electric lighting, enlightenment, festoon lighting,
   floodlighting, fluorescent lighting, gaslighting, glow lighting,
   height, high pitch, highlights, illumination,
   incandescent lighting, indirect lighting, irradiation, key,
   key signature, keynote, light and shade, lighting, low pitch,
   major, major key, mediant, mellifluence, mellifluousness,
   melodiousness, melody, minor, musical quality, musical sound,
   musicality, new philharmonic pitch, note, overhead lighting,
   pedal point, philharmonic pitch, philosophical pitch, pitch,
   radiation, register, spot lighting, stage lighting, standard pitch,
   strip lighting, subdominant, submediant, subtonic, supertonic,
   sweetness, timbre, tone, tone color, tone quality, tonic,
   tonic key, tune, tunefulness