It varies, even internally. Officially, yes, it's "package". "GNU Project" (capital "P") refers to GNU itself. "Project foo is part of GNU" is also common.

It varies, even internally. Officially, yes, it's "package". "GNU Project" (capital "P") refers to GNU itself. "Project foo is part of GNU" is also common. "A GNU project" isn't uncommon informally. On Savannah, they're "projects". The maintainers guide uses both---you can tell what was written early on, possibly by rms, vs. changes that happened later on.