I was, at first, confused by the term "caraco." If you've been around the costume or reenacting world but haven't had a chance to dig deeper into the term, what comes to mind is very likely JP Ryan's pattern of that name--a 3/4 length garment fitted with a pieced and box-pleated back.
However, a perusal of fashion plates illustrates that this is far too narrow a definition for "caraco." (In fact, I have yet to find an image of a 3/4 length garment combined with the term "caraco" but of course my search has been less than exhaustive--has anyone found an illustration or plate matching the two?)
(I am greatly indebted to Cassidy at A Most Beguiling Accomplishment for posting and providing text for [TEXT!YES!AMEN!] these images. All of the images and accompanying original text and dates that follow are from her excellent blog. Commentary my own.)
Many non-full-length--or, perhaps, what we could call "jacket" length--women's garments depicted in this type of primary document are called a "caraco." Some are simply called "caracos" but other variations are very common.
Maid is wearing a "caraco of pale buras" while her mistress wears a gown:
Caraco plisse [pleated] or Caraco a la Francaise:
Caraco a la Polonaise:
Caraco a la Levite:
1778 (Interestingly, a style intended to imitate the "Creole" dress of French North America. Accuracy of imitation is debatable...)
And my personal favorite, Caraco a l'Amazone:
1788 (Caraco varieties, at least per fashion plates, seem to have exploded in the late 1780s, each with their own unique nomenclature. I can't speak as to what is so very Amazonian about this caraco, or about affixing a giant green sunflower to one's hat.)
So, what is a "caraco?" My interpretation is that it isn't, in fact, a single garment, but a category of garments--much like "robe." As "robe" indicates a full-length garment, inclusive of multiple varieties with various construction techniques employed, "caraco" indicates a "jacket-length" garment inclusive of multiple variations and construction techniques. They seem to share a lack of stomacher and a back with pleats--either sacque pleats or box pleats to shape the fullness of the skirts.
Where did the term come from? Good question. Etymological sources note the similarity between the French "caraco" and the Spanish "caracol." Caracol means snail. Now, the French were certainly no strangers to creative garment naming practices (pet-en-l'air, Pierrot...), but I can't see a tie between a short jacket and a snail. Interestingly, however, someone did--in early Spanish-speaking North America a caracol indicated a type of short garment worn at night. Could the caraco have taken its name from this garment? I unfortunately cannot find any additional information about what this garment looked like--Spanish and Latin American clothing is not my forte.
The only other closely related French word I can come up with is "caracoler" which means "to prance" or to maneuver a horse as in dressage competitions (and, interestingly, in the latter usage meaning to turn about, may be related to the snail reference again--the tight spiral of a snail shell). [And aside--say that out loud. Ca-ra-co-lay. Isn't it a delightfully prancey onomatopoetic word?] Referring to clothing as "prancey" would certainly fall into French tongue-in-cheek clothing naming convention, so perhaps a caraco is a prancing jacket? Or perhaps for the similarity to a riding habit...minus the seriousness of that masculine-inspired ensemble?
Now....who used this term? Keep in mind that these plates are French. Did this term emigrate? Did the garment itself emigrate?
On one hand, we can, in my view, safely assume that the style did migrate overseas. Foreign visitors to the American colonies note that urban women dress in clothing "in the French fashion" (with some surprise for some--Dohla, a German soldier serving in auxiliary forces opposing the rebelling American colonists, is struck in each city he visits just how nice and fashionable everyone's clothes are). Caracos would certainly qualify as "French fashion." The term "caraco" does not, however, appear in any of the "usual suspects" of North American searches, per Hallie Larkin in her blog post on the questionable appropriateness of the JP Ryan caraco incarnation for American Revolution portrayals.
My final judgment call for my own caraco? I'll call it a caraco, putting on the airs I've earned reading French fashion magazines. But I'll accept that most of my colonial peers would likely refer to it as a jacket, a term that appears in primary sources from colonial America.