• A Tempo - (A tempo) On time
• Accelerando - (Accel.) Increase speed gradually
• Accent Mark - (>) Accent note
• Active Tones - The 2nd, 4th, 6th, and 7th degrees. In laymen's terms: Re, Fa, La, Ti.
• Alla Marcia - (Alla marcia) In march style
• Allegretto - (Allegretto) Merrily; Fairly rapid
• Allegro - (Allegro) Fast
• Andante - (Andante) Slowly
• Bass Clef - Also known as the F Clef.
• Bass Line - Bass melody
• Belt Out - When the vocal resonance used comes from the diaphragm; characterized by very solid, loud, rich sound.
• Cantabile - (Cantabile) In a singing or vocal style
• Chest Tone - The "modulation" resonance/register, where the voice used in singing comes from the chest (no duh). It's usually when one is transitioning gradually from one octave to another.
• Chords - Combination of three or more pitches sounded simultaneously.
• Clef - The symbol on the staff that gives definite names to notes
• Con brio - (Con brio) With spirit
• Crescendo - (Cresc.) Gradually louder
• Da capo - (D.C.D) Return to the beginning
• Decrescendo - (Decresc.) Gradually softer
• Diminuendo - (Dim) Softer by degrees
• Dolce - (Dolce) Sweetly
• Duple Time - Kind of rhythm that has 2 beats in a measure. Strong beat, followed by a weak beat.
• Dynamics - Loudness or softness of sound. Examples of terms that indicate dynamics: pianissimo, mezzo piano, mezzo forte, fortissimo, crescendo etc.
• Espressivo - (Espressivo) With expression
• Falsetto - Vocal register where the areas within the throat and the mouth are used in order to reach slightly higher tones; may also be used for modulation purposes. Not to be confused with your speaking voice because this register is used for ranges above the normal vocal range.
• F Clef - In laymen's terms, it signifies that it's what your left hand plays on the piano. Places Fa or F on the 4th line.
• Fine - (Fine) The end
• Flat - Half a step/key lower (those black little thingies on the keyboard); in vocals, this means you are off-key by a lower note.
• Form - Consists of musical phrases.
• Forte - (f) Loud
• Fortissimo - (ff) Very loud
• G Clef - In laymen's terms, it signifies that it's what your right hand plays on the piano. It places G or Sol in the second line.
• Grazioso - (Grazioso) Gracefully
• Harmonic Interval - 2 tones are sounded together.
• Head Tone - A very rich and powerful vocal sound that originates gets its power from your highest resonances. Not to be mistaken for belting out or diaphragm resonance. Not to be mistaken with falsetto either.
• Key - Ahk, I ran out of words so here's Dictionary.Com's description: "A tonal system consisting of seven tones in fixed relationship to a tonic, having a characteristic key signature and being the structural foundation of the bulk of Western music."
• Interval - Distance in pitch between 2 tones.
• La Melodia - (La Melodia) The melody
• Legato - (Legato) Smooth and connected
• Leggiero - (Leggiero) Light and airy
• Licks - From Status*: "A short solo, usually played heading in to or out of a verse."
• Marcato - (Marcato) Play with emphasis
• Melodic Interval - 2 tones are sounded one after another
• Melody - Succession of related tones that express an idea
• Mezzo-forte - (mf) Moderately loud
• Mezzo-piano - (mp) Moderately soft
• Misterioso - (Misterioso) In a mysterious manner
• Moderato - (Moderato) Moderate rate of speed; not so fast
• Nasal Register - Using the soft palate to produce a sound, usually a singer's last resort when the pitch is too high for the chest or the diaphragm to reach.
• OPM - Original Pilipino Music
• Passive Tones - The 1st, 3rd, 5th, and 8th degrees. In laymen's terms: Do, Mi, Sol, Do.
• Piano - (p) Soft
• Pianissimo - (pp) Very soft
• Pitch - Property of sound that identifies the highness and lowness of a tone.
• Poco a poco - (Poco a poco) By degrees
• Presto - (Presto) Very fast
• Quadruple Time - Kind of rhythm that has 4 beats in a measure. Usually the rhythm that is used for jazz music.
• Resonance - The prolongation of sound produced by vibration; in vocals, this is also called the register, from where a person gets his/her vocal technique from.
• Riffs - From Status*: "A unique series of chords and/or notes specific to one song."
• Ritard - (rit) Rowena—err, I mean, gradually become slower
• Rhythm - The regular flow of accented and unaccented beats (strong and weak).
• Scale - Musical "stairway" of notes ascending and descending within an octave.
• Scherzando - (Scherzando) In a playful manner
• Sempre - (Sempre) Always
• Sforzando - (sfz) Very strong accent
• Sharp - Half a step/key higher (those black little thingies on the keyboard); in vocals, this means you are off-key by a higher note.
• Simile - (simile) Same as indicated previously
• Slight Accent - (—) Sustain
• Staccato - (Stacc.) Detached, short
• Staff - Made up of 5 lines and 4 spaces where notes are written
• Syncopation - A shift of accent in a normally unaccented beat
• Tempo - "Speed" in music. Examples of terms that indicate tempo: Largo, Andante, Ritardando, Alla marcia, etc.
• Teneramente - (Teneramente) With tender emotion
• Time Signature - Represents rhythm (if it's duple time, triple time, or quadruple time). It's the "fraction" written after the clef. The "numerator" indicates how many beats there are in a measure. The "denominator" tells what kind of note gets 1 beat.
• Tones - Musical sounds
• Tranquillo - (Tranquillo) Quiet, calm
• Treble Clef - Also known as the G Clef.
• Triple Time - Kind of rhythm that has 3 beats in a measure. Strong beat, followed by 2 weak beats.
• Tune - Succession of tones
• Variation - An altered version of particular form, differentiating itself by melodic additionals, ornamentation and/or changes in harmony, rhythm, key etc.
• Vivace - (Vivace) Fast and Lively

*Thanks to Status for helping me find the words to describe some of the guitar terms. As you can see, I was so tired writing these off the top of my head that when it came to inserting the last term, "key", into the glossary (which should be very simple), I had to go to dictionary.com.