Here are some other resources on musical instruments. Please also see the "Ethnomusicology/World Music" and "Musicology/Music History" sections.
"Aerophone: Sound produced by vibrating air, caused by breath or wind, within a column or tube. Examples include shawms, clarinets, flutes, pipes, trumpets, and horns."--Wesleyan University Virtual Instrument Museum
"Chordophone: Sound produced by a vibrating string or cord under tension. Usually acoustically enhanced in conjunction with a resonating chamber of air. Examples include fiddles, zithers, psalteries, musical bows, harps, and lutes."--Wesleyan University Virtual Instrument Museum
"Idiophone: Sound produced by vibrating a solid material which is free of tension. Examples include shakers, scrapers, wood blocks, cymbals, gongs, and xylophones. "--Wesleyan University Virtual Instrument Museum
"Membranophone: Sound produced by a vibrating skin or vellum stretched over an opening. Examples include all drums, regardless of shape, that employ a tensioned membrane."--Wesleyan University Virtual Instrument Museum