1	Interval		_____	The volume(s) of a musical sound
2	Drone		_____	The underlying structure of a musical performance based upon repetition and new material
3	Chordophone		_____	A tone's frequency level, measured in Hertz
4	Idiophone		_____	An instrument that produces sound when a stretched skin vibrates
5	Rhythm		_____	A melodic decoration
6	Dynamics		_____	A set of pitches arranged in an ascending or descending order
7	Beat		_____	The relative rate or speed of a beat
8	Scale		_____	An instrument that requires air to produce sound
9	Timbre		_____	An instrument that produces sound when struck, shaken or scraped
10	Form		_____	An instrument that produces sound when a string vibrates
11	Membranophone		_____	The distinctive character or quality of a musical sound
12	Melody		_____	Patterns in time; durations of sound
13	Sachs-Hornbostel		_____	A tune; a sequence of notes that make up a musical phrase
14	Pitch		_____	A regular pulsation that underlies music
15	Ornamentation		_____	A continuous low sound
16	Meter or Time Signature		_____	The distance between two pitches
17	Aerophone		_____	A system of classification of musical instruments
18	Tempo		_____	A division of beats into regular groupings of 2, 3, 4 or more beats