"Coup" refers to the way the previous, legitimately-elected government was overthrown, before the "rebellion" had even started. It's still unclear who really managed to escalate the situation using snipers (who were never found, afaik), and how bands of "revolutionaries" were armed and organised. We know the US were pushing hard for regime change, thanks to the Nuland intercept, and the personalities reported as US-connected in that intercept were the ones actually taking power.

History will usually call "revolutions" the overthrown of unpopular governments doing outrageous things, and "coup" the overthrown of legitimacy-elected governments doing things that only a minority considered objectionable. You can see how this could lead people to judge the Ukrainian series of events in different ways.

Depends who you define as "government". Do you mean the ousted governemnt of Viktor Yanukovych? Or do you mean the government of Arseniy Yatsenyuk? Or the new government of Petro Poroshenko?

Revolutions are such messy things.