The word "revolution" is defined as meaning "an overthrow or repudiation and the thorough replacement of an established government or political system by the people governed."
Based on this definition, yes - the American Revolution was a genuine revolution. The people who lived in the thirteen American colonies, who had been governed under colonial practices set out by the King and Parliament of Great Britain, renounced that system and replaced it with a new governmental structure of their own creation.
The colonial assemblies, which had exercised local control under the direction and with the approval of Parliament, were disbanded by the colonists or closed by order of Parliament. In reaction to British attempts to continue to exercise control in many facets of business, trade, and daily activities, the colonies came together, eventually gathering for the Second Continental Congress which issued the Declaration of Independence severing "the Political Bands which have connected them (the colonists) with another (Great Britain)."
In the Articles of Confederation, and later in the Constitution, the new country set out the framework of its new government.