Nosism: The use of 'we' in referring to oneself – would it also be called nosism if using 'we' to refer to someone else (other than oneself)?
The Dean of our College always addresses me thusly, "How we doin'?" (instead of the standard "How are you doing?"). I don't think he intends it as a corporate inquiry (i.e. keeping a pulse on the College and student life at large) but rather just a friendly personal greeting directly to me (he's a farm boy from Oklahoma so maybe it's a colloquialism).
Is referring to oneself in the third person also a form of nosism? For example, there was a whole episode of Seinfeld in which George Costanza begins referring to himself in the third person ("George is getting upset!") after picking up on the conversation patterns of another character who does the same ("Jimmy likes you!" says Jimmy to Elaine who has mistaken another guy who she likes as Jimmy not realizing that the guy addressing her is using the third person.)