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 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.