I happen to prefer the word "work", not finding it pretentious as Oteri does, but rather more down to earth, a reminded that making music is a form of labor, an ongoing concern to be integrated into one's life, and a concern in which one can be ordinary or extraordinary, or can experiment and fail or succeed, and can have the status of in-progress, finished, or abandoned. Heck, I even like the construction "art work", in which the two terms, one lofty and mysterious, the other familiar like an old shoe, bounce roughly against one another. But perhaps we do need to take the term "work" back from the aesthetic philosophers, particularly the German romantics, who attempted to place "art" and "work" at eye-to-eye.*
But the term piece is useful, too, and Oteri gets it right. It's more particular than "work", which can stand for everything one does. Piece instead carries the sense of being a part of a larger whole. This could be the larger whole of music itself, or a platonic ideal, of which the piece is but a shadow. It could also be pejorative, in the sense of piecework, part of a mechanical production line. But I do think that this sense was very important to some of the composers in the experimental tradition to whom I looked up as a student, and continue to be challenged by. With Alvin Lucier, or with La Monte Young, the question of the number of items in their catalogs was often difficult to answer. The items were not stable quanta, but rather dynamic fields of ideas which congregated or segregated as the composer came to discover, define, or clarify what belonged, or what didn't in one piece or another. This experimentation with the extent and limits of a piece, and the consequent willingness to let go of a fixed notion of a work's identity, is something that I've dearly missed in other musical traditions. The New Complexity folk, in particular, for all their cycles and systems, seem at core to be reinforcing a very conservative attitude about the nature of a piece, and like most musicians, the idea of a piece is closely identified with the subject of a commission. Isn't this forcing a reconciliation of the music its commodification?
I must admit to one strange, almost ritual, use of the word piece, as a substitute for the proper title. Rather than say the title, I'll say "the trombone and piano piece", as if uttering the title itself is taboo, an interference with some magic inherent in the name. Or maybe, the proper title, like proper names, is a signal of an intimacy that one doesn't wish to flay about in public, and the magic is present in that intimacy, not the name itself.
* Norman O. Brown's essay, "My Georgics", in the collection Apocalypse and/or Metamorphosis, is a fine celebration of work. Even better, go back and read the Georgics of Virgil, always an encouragement to do one's own work.
Addendum: after I posted the above, Gordon Mumma wrote me:
I find some discomfort with various commonly used words for what we do. Never like the term "show" for a concert performance or recital. A "show" is for promoting or selling bloated automobiles and other such new junk.
"Work" fits for what I'm doing when I make a "composition". "Composition" then becomes a noun and the confusion of "work" as a noun or verb or whatever is minimized. "What am I composing?" becomes a rational question.
I can take the group "work of art", or "art work", generally or sometimes, depending on the context.
Doing my taxes is certainly "work" and for my situation it consumes more unrewarding perspiration effort than any other required activities except perhaps for when I was required to be in "committees" to decide the career fate of others in academia.
"Piece" is also problematical because it has the implication of a fragment or part of something. I think it was La Monte who made a "Piano Piece" that consisted of a piece of a piano -- a piano leg as I recall -- displayed on the stage.
When I'm asked what I'm working on these days, I have to struggle a bit with my answer. "I'm working on a piece for two pianos" is satisfactory because I'm actually working on a piece of the planned composition. But my word "piece" in the answer is most likely heard/understood differently.
Sometimes an answer to the above question is easier by using a specific title, as "EX STREAM for Tomoko Mukaiyama" in my recent composition RENDITION SERIES. Easy there because the EX STREAMS are parts of the larger composition. Just as a "Sarabande" is part of Sebastian Bach's FRENCH SUITES.
A lower-brow possibility is the question "what are you making these days?", though it reminds me from my late teen-age days of the question "who are you making these days?".
An amusing blur of contexts. You suggestion of the idea "dynamic fields of ideas which congregate or segregate as the composer... discovers, defines..." etc. is the most inclusive definition I've seen. Though you suggest the relevance to the creative work of Alvin Lucier or La Monte Young, I like it because it allows the appearance of the "process" of composition. and as you say, isn't "forcing a reconciliation of the music to its commodification."
Sometime around the turn of just the past century I was asked from an academic source for a definition of the word "music". After some thought about the context of the question I gave them this quasi-pompous but largely inclusive reply: "Music is a network of ideas, interconnections and creative decisions, presented in time as patterns and relationships of sounds."
I've no problem with using the word "sounds" above, because I consider "silence" as one of the components of "sounds'.
Enough of this here, and back to slugging through my taxes. Best, -- Gordon