Written language isn't the same as technical language.
For my point of view and others around me call it number it.
Reasoning behind it, if your on the telephone/V.C. with the contractor how much easier is it to say "in note one" rather than the alternative "in the note" (which could mean any note on the drawing).
In the days of hand drafting would you want to erase the note to rewrite it with a 1. at the front because note 2 was added at Rev B. Days gone by, but a lot of what we do now was set back in the days of the goose feather pen.