That's the thing, they had a number of different terms for referring to them and they had no official convention about how they were identified. And some identities changed over the course of time, reigns, etc. But if you had were asked people of 'the colonies' pre 1776 whether they were subjects of His Majesty's Crown in England, or not, what do you think they'd have said?
Early on they were Roanoke, Plymouth, Jamestown, Virginia, Carolinas, New England, geographic descriptors, bay x or river y, point a, b or c, Virginia Company charters, London Company, commonwealth overseas, the realm in America, land grants, 'plantacions,' new world, outposts, forts in xxx, Capt or Col so and so's expedition, across the seas, the x or y colony, colonies, early cities and counties etc., etc., etc. And that's not getting into names of locations that changed over time, or those that we're named specifically after locations in England. I've never seen a word count on the topic, but I read a lot of old books and I'm certain it's easily in the triple digits. (Google doesn't read old books by the way.)
Over time, the geo-political boundaries of the 13 colonies resembling our present day states were surveyed and took shape, but they didn't start that way. They took shape nearer to the time of the revolution and onward, but were scattered, spotty and varied over degrees of time beforehand.
Isn't it just simpler to organize them all loosely under the common heading that they all had in common going back to Roanoke, regardless of the period, with a few exceptions, whether they at that time had the presence of mind or awareness to or not in the time that they lived? ie: British America, British Colonial America.
Whether agreed on the previous points or not, it's not logical or consistent to refer to places post-1776, as United States of America or USA abbreviated, clearly linking and identifying the nation state of geo-political dominion and control, without doing the same for those locations prior to 1776.
Every rule has exceptions and this should be one imo.