Hi,
Generally instruments are divided into three categories (string, wind and percussion), which of course leaves off newer developments such as synthesizers/edrums/etc. There are other classification schemes with more classes.
The Greeks had two families of instruments Animate (voice) and Inanimate. They subdivided the Inanimate into string and wind. The Arabs apparently had a similar two group classification. Later on percussion was given a classification of some sort.
Pianos were developed after the traditional three family classification, which is part of the reason for the piano's awkward inclusion in percussion. Worth noting that percussion and string have been classed as one entity in the past because of their common need for tensioning to produce the desired note.
Here is some discussion of the issues from Grove Music Online; Instruments, classification of:
"Our own present-day practice does not amount to much more. Sound-instruments are divided into three major categories: string instruments, wind instruments and percussion instruments. This cannot be defended even on the grounds that it satisfies day-to-day requirements. A large number of instruments cannot be fitted into any of the three groups without placing them in an unnatural position, like the celesta, which, as a percussion instrument, is brought into close proximity to drums and so on. As a remedy one introduces a fourth group under the disconcerting heading ‘miscellaneous’ – in any systematic grouping an admission of defeat. Moreover, the current classification is not only inadequate, but also illogical. The first requirement of a classificatory system is surely that the principle of demarcation remains the same throughout for the main categories. Our customary divisions, however, follow two different principles, string instruments being distinguished by the nature of the vibrating substance but wind and percussion by the mode of sound-excitation – ignoring the fact that there are string instruments which are blown, like the Aeolian harp, or struck, like the pianoforte. The customary subdivisions are no better. Wind instruments are divided into woodwind and brass, thus giving a subordinate criterion of differentiation, namely, material, an unjustifiable predominance and flagrantly disregarding the fact that many ‘brass’ instruments are or were once made of wood, like cornetts, serpents and bass horns, and that in any case many ‘woodwind instruments’ are optionally or invariably made of metal, as flutes, clarinets, saxophones, sarrusophones, tritonicons etc."
It's all weird and reminds me of when I puzzled over where to put my reggae records and my grade school wonderment that despite having Irish/Scottish parents, I was apparently a caucasian...
Patrick
