Accent > Marking above or below note head that indicates note is to be stressed with emphasis.
Accidentals Sharps, flats, or naturals that indicate notes other than those indicated by the key signature.
Arpeggio Chord in which the notes are separated to produce a broken effect.
Asymmetrical Meter Meter in which the beats cannot be divided equally into groups of two or three.
Augmented An interval or chord that is one half step smaller than minor or perfect.
Authentic Cadence Cadence from V to I at the end of a musical phrase.
Bass Staff The lower of the two staves in the grand staff containing low pitches.
Block Chord Chord in which all the notes are played simultaneously. 
Borrowed Chord Chord taken from a parallel major or minor key.
Cadence Last two chords in a musical phrase.
Cantus Firmus Main line or phrase composed in voice leading.
Circle of Fifths Pattern of notes used to show key signatures and their relationships in a clock diagram.
Compound Meter Meter in which the beat is a dotted note.
Consonance Sound resulting from an interval or chord that is pleasant or resolved.
Counterpoint Line written against the cantus firmus in voice leading.
Crescendo Dynamics marking that indicates increasing in volume.
Deceptive Cadence Cadence in which the penultimate chord is V and the second chord is anything but the expected tonic.
Decrescendo Dynamics marking that indicates decreasing in volume.
Development Second section in a piece of music written in sonata form or fugue form that develops the themes introduced in the exposition.
Diminished An interval or chord that is one half step smaller than minor or perfect.
Dissonance Sound resulting from an interval or chord that is harsh or unresolved.
Duple Meter Meter in which the beats can be grouped by twos.
Dynamics Expression markings that indicate the loudness or softness of music.
Eighth Note Filled in note with flag that represents a certain duration of a beat indicated by the time signature.
Enharmonic Two intervals that share the same distance but different spellings, ex. aug 2nd, min. 3rd.
Exposition First section of a piece written in sonata form or fugue form that introduces the main themes.
Flat Accidental that indicates that the note that follows it should be lowered one half step.
Grand Staff Both the treble and bass staves linked together by a bracket.
Half Note Hollow note with no flag that represents a certain duration of a beat indicated by the time signature.
Harmonic Interval Interval in which both notes are played simultaneously.
Harmonic Minor Scale Form of minor scale that is the equivalent of the natural minor with a raised 7th scale degree.
Intervals Distance between notes that make steps or skips in music.
Key Signature Marking at the beginning of a measure that indicates which notes will be played most often.
Leading Tone One half step down from the tonic. The 7th scale degree that leads to the tonic.
Legato Expression marking that indicates notes are to be played smooth and connected.
Major Key Key that sounds bright. Found by going up one half step from last sharp or indicated by second to last flat.
Major Scale Scale that follows the pattern of whole and half steps from any two "C's" on the piano.
Measure Distance between two bar lines in a piece of music, also called one bar.
Melodic interval Interval in which the notes are played separately.
Melodic Minor Form of minor scale that is the equivalent of the natural minor with raised 6th and 7th scale degrees ascending, and the natural minor descending.
Minor Key Key that sounds dark. Key name can be found by using the relative minor key of major keys
Modulation The process of changing from one key to a closely related key, those that differ in one accidental.
Natural Minor Scale Scale that follows the pattern of whole and half steps from any two "A's" on the piano.
Non-Harmonic Tone Note played along with a chord that is note a traditional note of the chord.
Octave The distance between two keys of the same letter name, also the interval of an 8th.
Picardy Third Major third in the tonic chord in a minor key. Used to produce a resolved major sound at the end of a phrase in a minor key.
Plagal Cadence Cadence from IV to I at the end of a musical phrase.
Quarter Note Filled in note with no flag that represents a certain duration of a beat indicated by the time signature.
Recapitulation Final section in a piece of music written in sonata form or fugue form that repeats the themes presented in the exposition, and returns to the original key if modulation has occurred.
Relative Minor Minor key that shares the same key signature with a major key. Found by going down 3 half steps from the major key name.
Rondo Form in music that has a recurring section, the most common being ABACA and ABACABA.
Root Tonic note of a chord. The lowest note when in root position.
Sharp Accidental that indicates that the note which follows it should be raised one half step.
Simple Meter Meter in which the beat can be divided by two.
Sixteenth Note Filled in note with two flags that represents a certain duration of a beat indicated by the time signature.
Slur Curved line around note heads that indicates those notes are to be played legato.
Species one Counterpoint Form of voice written composition that is note-against-note.
Staccato Dote above or below note head that indicates articulation of the note is short.
Time Signature Symbol at the beginning of both staves that indicates the number and length of beats in a piece of music.
Treble Staff The top staff in the grand staff containing higher pitches than the bass staff.
Triad A chord built in thirds that includes a root, (tonic) third, and fifth.
Triple Meter Meter in which the beats can be grouped by threes.
Whole Note Hollow note with no stem that represents a certain duration of a beat indicated by the time signature.