Where do you suppose the term "massacre'' came from that describes this event

Answer;

It was a political propaganda term used by Paul Revere in the etchings he created after the incident.

Explanation;

When Paul Revere first began selling his color prints of "The Bloody Massacre perpetrated in King Street" in Boston, he was doing what any like-minded patriot with his talents in 1770 would have done. He did it faster and more expeditiously than anyone else, including two other artist-engravers who also issued prints of the Massacre that year.

Assuming you're referring to the "Boston Massacre," the word "massacre" was used because it sounded much worse than what it actually once--since it was easer to rally support around a cause that sounded like a "massacre" instead of just a few people being killed.