Tanto - Much, so much.
Tempo - The rate of speed in a musical work.
Tempo primo - Return to the original tempo.
Teneramente - Tenderly.
Tenor clef - The C clef falling on the fourth line of the
staff.
Tenuto, ten - Hold or sustain a note longer than the indicated
value, usually not as long a duration as the fermata.
Ternary form - Three-part form in which the middle section
is different from the other sections. Indicated by ABA.
Terraced dynamics - The Baroque style of using sudden changes
in dynamic levels, as opposed to gradual increase and decrease
in volume.
Tertian harmony - A term used to describe music based on
chords arranged in intervals of thirds.
Tessitura - The general pitch range of a vocal part.
Texture - The term used to describe the way in which melodic
lines are combined, either with or without accompaniment. Types
include monophonic, homophonic, and polyphonic, or contrapuntal.
Theme - The musical subject of a piece (usually a melody),
as in sonata form or a fugue. An extramusical concept behind a
piece.
Theme and variations - A statement of musical subject followed
by restatements in different guises.
Theory - The study of how music is put together.
Third - The third degree of the diatonic scale. Also, the
interval formed by a given tone and the third tone above or below
it, e.g. c up to e, or c down to a. Intervals of the third may
be major, minor, diminished, or augmented.
Through-composed - A term used to describe a song in which
the music for each stanza is different. The opposite of strophic.
Ti - In solmization, the seventh degree of the major scale.
Also called the leading tone.
Tie - A curved line over or below two or more notes of
the same pitch. The first pitch is sung or played and held for
the duration of the notes affected by the tie.
Time signature - Synonymous with meter signature.
Tonality - The term used to describe the organization of
the melodic and harmonic elements to give a feeling of a key center
or a tonic pitch.
Tone - A note; the basis of music.
Tone clusters - The simultaneous sounding of two or more
adjacent tones.
Tonguing - On wind instruements, articulation with the
tongue.
Tonic - The first note of a key. Also, the name of the
chord built on the first degree of the scale, indicated by I in
a major key or i in a minor key.
Tono - Tone, key, pitch.
Tosto - Quick.
Tranquillo - Tranquilly; quietly; calm.
Transposition - The process of changing the key of a composition.
Tre - Three. Used with other terms, e.g. a tre voci, in
three parts.
Treble clef - The G clef
falling
on the second line of the staff.
Triad - A chord of three tones arranged in thirds, e.g.
the C-major triad c-e-g, root-third-fifth.
Trill, tr - A musical ornament performed by the
rapid alternation of a given note with a major or minor second
above.
Triple meter - Meter based on three beats, or a multiple
of three, in a measure.
Triplet -
A group of three notes
performed in the time of two of the same kind.
Troppo - Too much. Used with other terms, e.g. allegro
non troppo, not too fast.
Turn -
A musical ornament characterized
by the rapid performance of a given note, the major or minor second
above and below, and a return to the given note.

Tutti - All. A direction for the entire ensemble to sing
or play simultaneously.
Twelve-tone technique - A system of composition which uses
the twelve tones of the chromatic scale in an arbitrary arrangement
called a tone row or series. The row may be used in its original
form, its inversion, in retrograde, and in the inversion of the
retrograde. The system was devised by Arnold Schoenberg in the
early 20th century.
Una corda - Soft pedal.
Unison - Singing or playing the same notes by all singers
or players, either at exactly the same pitch or in a different
octave.
Un peu - A little. Used with other words, e.g. un peu piano.
Un poco - A little.
Upbeat - One or more notes occurring before the first bar
line, as necessitated by the text for the purpose of desirable
accent. The unaccented beat of a measure.
Variation - The manipulation of a theme by the use of melodic,
rhythmic, and harmonic changes.
Vibrato - Repeated fluctuation of pitch.
Virtuoso - A brillant, skillful performer.
Vivace - Lively, brisk, quick, and bright.
Vivo - Lively, bright.
Volti subito - Turn [the page] quickly.
Whole note/rest - A note/rest equal to two half notes and
four quarter notes. 
Wind instrument family - Instruments in which sound is
produced by the vibration of air, including brass and woodwind
instruments.
Woodwind family - Instruments, originally made of wood,
in which sound is produced by the vibration of air, including
recorders, flutes, clarinets, saxophones, oboes, and bassoons.
Leonard, Hal, Pocket Music Dictionary, Hal Leonard Publishing
Corporation, 1993.
Something to Sing About, G. Schirmer and Co., 1984.