Definitions
HARMONY    (1) relative minor key of a major key - the minor key that shares a key signature with the major key and whose tonic is on the sixth degree of the major scale.  Example:  F major, d minor.
(2) parallel minor key of a major key - the minor key that has the same tonic note as the major key.  Example:  F major, f minor.
(3) closely related keys - keys who share a key signature or whose key signatures are adjacent on the circle of fifths, i. e. keys that have no more than one sharp or flat difference in their key signatures, including relative minor and major keys.
(4) cadence - a two-chord progression that marks the end of a phrase, section, or piece, and defines the tonality.  Common cadences are:
        - authentic cadence     V - I or V - i
        - plagal cadence        IV - I or iv - i
        - half cadence        I - V, IV - V, etc. (any cadence ending on V)
        - deceptive cadence    V - vi or V - VI
(5) cadential formula - a frequently used progression of three or four chords ending in a cadence.  Examples: IV - V - I; ii6 - V - I; I - IV - V; etc.
(6) circle of fifths progression - a chord progression where the roots of the chords descend (or ascend) by fifths.  
(7) diatonic circle of fifths progression - a circle of fifths progression utilizing only chords that are diatonic within a key and one diminished fifth root movement (7 fifths total).
(8) chromatic circle of fifths progression - a circle of fifths progression from one dominant seventh chord to the next, utilizing only perfect fifth root movement (12 fifths total).
(9) modulation - key change within a composition, generally not shown in the key signature.
(10) pivot chord - a chord common to both the key we are modulating from and the key we are modulating to.
(11) common chord modulation - a modulation using a pivot chord
(12) chromatic modulation - a modulation to a new key without the use of a pivot chord, involving chromatic movement in one or more voices.
 
MELODY    (13) motive - a short, recognizable melodic statement.
(14) inversion - a statement of a motive or melody where the directions of the intervals are reversed.
(15) ornamentation of a motive - embellishment of a motive through neighbor or passing tones, etc.
(16) sequence - repeated statements of a motive, each time starting on a subsequent scale degree.
(17) augmentation - a restatement of a motive or melody with increased rhythm values.
(18) diminution - a restatement of a motive or melody with decreased rhythm values.
RHYTHM    (19) simple meter - a meter in which the basic beat divides in 2's:  4/4, 3/2, etc.
(20) compound meter - a meter in which the basic beat is a dotted note value and divides in 3's:  6/8, 9/16, etc.
(21) duple meter -  a meter with 2 basic beats per measure: 2/4, 6/8, etc.
(22) triple meter - a meter with 3 basic beats per measure: 3/4, 9/8, etc.
(23) quadruple meter - a meter with 4 basic beats per measure: 4/4, 12/8, etc.
(24) irregular meter -  a meter containing groupings of both 2 and 3 notes:  5/8, 7/8, etc.
TEXTURE    (25) texture - the way that melodic, rhythmic, and harmonic materials are
    woven together in a musical composition.
(26) monophonic texture - consisting of one melody with no accompaniment.
(27) polyphonic texture - consisting of two or more simultaneous melodies that harmonize.
(28) homophonic texture - consisting of a melody with chordal accompaniment.
POLYPHONIC    (23) canon - a piece consisting of a melody performed in several voices,

FORMS             where each voice starts the melody at a different time; a round.

&TECHNIQUES
(29) counterpoint - 1) the technique of writing two or more melodies that sound simultaneously and harmonize 2) a melody written to harmonize with a melody in another voice.
(30) imitation/imitative counterpoint - in a polyphonic composition, the restatement of a melody in a different voice.
(31) invention - a polyphonic composition with two or three voices that uses imitative contrapuntal techniques.
(32) fugue - a polyphonic composition with three or more voices based on a subject which is stated in one voice and imitated in the other voices.
(33) subject - a melodic theme in an invention or fugue; longer than a motive.
(34) countersubject - a melody that accompanies a subject in a different voice and recurs each time the subject is restated.
(35) invertible counterpoint/double counterpoint - a restatement of a passage of counterpoint where the position of the two voices is reversed, i. e. the melody that was in the upper voice appears in the lower voice and vice-versa.
HOMOPHONIC    (36) phrase - a four-measure melodic unit ending in a cadence.

FORMS
(37) period - two phrases in an antecedent-consequent (question-answer) relationship where the first phrase ends in a non-final cadence and the second phrase ends in a final cadence.
(38) repeated phrase - exact repetition of a phrase, including the cadence.
(39) parallel period - a period where the second phrase closely resembles or at least begins like the first phrase, with the main difference being at the cadence.
(40) contrasting period - a period where the second phrase is completely different than the first phrase.
(41) modified parallel period - similar to a parallel period except that the second statement of the phrase has been modified by ornamentation, transposition, or inversion.
(42) binary form - a two part form where the first part does not return; AB or ||:A:||:B:||  (Each part may be repeated.)
(43) rounded binary form - similar to the binary form, except that the B section is short, generally half the length of the A section, and the A section returns in shortened form.  ||:A:||:BA:|| (always with repeat signs), where if A is 8 measures long, B and the return of A are each 4 measures.
(44) ternary form - three part form similar to the rounded binary, ABA or ||:A:||:BA:|| where the B section and the return of the A section are each at least as long as the original A section.
(45) theme - a melodic shape used in homophonic forms, at least as long as a phrase.  May contain several motives.
(46) rondo form - a large form in which the first section (which can be a period or a binary, rounded binary, or ternary form) returns two or more times, alternating with other sections; ABACA or ABACABA, etc.
 (48) sonata allegro form - a large form consisting of three main sections: the exposition, in which thematic material is introduced (at least two main themes); the development, in which material from the exposition is used in new and different ways; and the recapitulation, in which the material from the exposition is restated.  The harmonic plan is as follows:
        Exposition:    Theme I    Theme II    Closing theme
            I or i*    V or III    V or III
        Development:    modulation through various keys; ends on V
        Recapitulation:    Theme I    Theme II    Closing theme
            I or i    I or i    I or i
    *In major keys modulation to the dominant usually occurs; in minor keys modulation to the     relative major key.            
(49) theme and variations form – a large form based on a theme (usually in binary, rounded binary, or ternary form).  The theme is followed by a series of modified restatements, or variations.