For an identity we might produce just a logo, or the full monty including brochures, stationery, posters, signage, and tea towels. OK, probably not the tea towels.
By 'communications' we mean anything from posters and leaflets to signage and exhibition stands - whatever you need, and whatever's best to make your point.
Yes, documentation is just another kind of communication. But for the sake of argument, documentation is also a bit more complex - a booklet rather than a brochure, or a series of reports rather than one poster.
Sure, 'online' typically means a website, but it could also be an email newsletter, an interactive banner, a web-based campaign or service. So websites and other 'online stuff' really.
For us, this includes research, writing and editing, and though usually part of producing something like a booklet, report, or newsletter, could be a purely editorial project on its own.