And since I'm full of shitty hot-takes... Most English people use the word "barbecue" in a different way than someone from the areas of the USA where it is an entire cuisine(s) unto itself would use it.

And there's sectarianism in barbecue.

In much of the world "barbecue" has been bastardised to mean "stuff cooked over flame", but this definition is ridiculous in barbecue's homeland/heartland.

If we look, objectively, at the cuisine that encompasses "American Barbecue" - it is far more specific. Damn near anything can be cooked over/with wood/gas/coal/charcoal flame, but that is not actually classic BBQ cuisine. (Will now use BBQ for brevity.)

Etymology tells us that "barbecue" comes originally from the Arawak/Taino word "barbacoa" - but that's a whole other story and a branch I can go down some other day.

However, relatively early in colonial America in the South, a style of cooking meats evolved using wood smoke and long slow cooking times, whereby the smoke did much of the work and the heat was much lower, i.e. indirect.

Smoked meats (and fishes and etc.) of various descriptions have long histories in many cuisines. But somehow the Taino word Barbacoa got corrupted in North American English to refer to a distinctive cookery style.

The early colonial era explore John Lederer refers to the word "barbecue" in a letter from 1672, from the Appalachian region. He talks about it here: https://books.google.co.uk/books?id=VAsOAAAAIAAJ&q=barbecue&dq=barbecue&hl=en&ei=KwkATvyQEsydgQeRt4zNDQ&sa=X&oi=book_result&ct=result&redir_esc=y

George Washington talks about going to a "barbecue" in Alexandria, Virginia, in 1769. I refer you to his diaries in the National Archives. https://founders.archives.gov/documents/Washington/01-02-02-0004-0013-0027

There are only a few basic components to American BBQ - 3 mandatory and 2 optional.

Mandatory component 1: Meat. Ancestrally, pork appears to be the original meat used, although numerous other meats are now BBQ'd, but the original in Virginia/Carolinas/Georgia was pork. Regional variants will be discussed below.

Mandatory component 2: Wood smoke. There are numerous types of wood that can be used to make barbecue. But it is wood smoke that does the work. Again, regional variants will be discussed below.

Mandatory component 3: Time. This is a slow cooking technique. The heat is low and indirect, even if some specific practitioners might finish off a particular BBQ specialty briefly on direct flame. However, 6-12-18 hour and even longer smoking times are used.

Optional component 1: Pre-cooking seasonings. This includes marinades, dry rubs, wet rubs, etc. These vary WIDELY both in general regional terms and by individual practitioner. Sometimes one uses nothing. Just the meat.

Optional component 2: Some sort of sauce late in smoking or used as a condiment after smoking. I'd also include a category here referred to as a "mop" - a lighter sauce mopped onto the cooking meats while smoking. These also vary widely and stir emotions.

Now, with these 5 variables, you already have numerous, indeed almost infinite permutations. A number of these permutations have evolved regionally in some general regional styles of BBQ.

I will attempt to survey the main regional styles of American BBQ, but I will, of necessity, have to paint with a broad brush and make some sweeping generalizations that some BBQ nut will, no doubt, take offense at. I apologize in advance.

There are four major regional BBQ cuisines and some minor ones worthy of mention. And a few borderline things that are arguably BBQ or not.

Carolina BBQ: Predominately pork, often the entire pig. Smoke: Hickory. Usually with a rub. Usually with a mop during cooking. Served pulled, sliced, or chopped. Oak is a lesser used wood, but not unheard of.

Within Carolina-style BBQ there are a bewildering array of regional variations as to sauces. South Carolina has a mustardy-yellow sauce. Eastern NC tends to have a vinegary quite loose sauce. There are others.

Western North Carolina BBQ often just uses the shoulder of the pig.

As a procedural point, I would like to add that, when I am surveying these regional BBQ styles, I am noting the main features. As a practical matter, there's lot of BBQ-creep. A BBQ joint in NC will likely have some beef and chicken too. I'm surveying the highlights here

So "But I had a really good BBQ turkey slice in Arkansas" is a perfectly fine thing to say. I am simplifying a vastly complex subject here.

Memphis-style BBQ is centered in the Tennessee city of the same name. It also tends to use hickory smoke. The center of gravity here is pork ribs, either with a dry rub or wet, with sauce. Both are valid styles. And pork sandwiches. In practice, the sauces vary greatly.

In an interesting twist, one of the great Memphis BBQ purveyors, Charlie Vergos, does BBQ lamb ribs and they are very good.

The next great style of BBQ is Kansas City. Woods used for smoke vary, and a wide variety of meats and cuts are used. A key distinguishing feature is a thick, tomato-based sauce of ketchup-consistency, both loved and derided.

A particular feature in KC BBQ is that, best I can tell, this is where the "burnt end" comes from. https://en.wikipedia.org/wiki/Burnt_ends  Also, generic "BBQ Sauce" in a packet or bottle in the supermarket is often Kansas City style BBQ sauce.

I have to say, having only barely been to KC, this is the style of BBQ I have the least familiarity with.

Then there is Texas Barbecue, which owes much to German and Czech immigrants. There are regional variants within Texas, but the classic heart of this cuisine is Central Texas, particularly a belt around Austin.

Again, there are some variants in wood, but this is where mesquite (unavailable in the other regions except as an import) is a valuable addition to the chef's arsenal.

Texas BBQ is characterized by beef brisket and sausages, but will almost invariably also have ham and pork ribs. Turkeys and chickens are common too. Pulled pork happens, but a purest might consider it a Carolina import.

I present to you the BBQ menu from Angelos BBQ in Fort Worth. This is the BBQ of my university days and close to my heart. But this gives you the idea.

Sauce is often an afterthought and even unnecessary in good TX BBQ. Here the smoke does the work. Rubs and mops and marinades and such are considered by some to range from unnecessary to foreign perversions.

(Remember, Texas was once independent)

There are some lesser known BBQ cuisines in smaller regions. Sometimes these are a subset or draw heavily on one of the regional cuisines.

There is, in Alabama, a weird white sauce used on barbecued chickens. I had it once and it wasn't bad. cf https://www.kmuw.org/post/cooking-fire-alabama-white-sauce

There is a belt of towns in Kentucky wherein mutton is BBQ'd. This is practically the only place in the UK where mutton figures in the cuisine.

And, as @opendna has mentioned, there's "Central Coast" or "Santa Maria" BBQ in California. This is, IMHO, still BBQ, but one that pushes some of the variables. It uses oak, and higher temperatures and more direct cooking and quicker times than the other styles.

However, the classic Santa Maria BBQ's tri-tip (a particular bottom sirloin cut of beef) done over oak is a fine dish and I consider it BBQ .

I think there is a serious doctrinal question as to whether Hawaiian luau, cooked in a pit called an imu, counts as BBQ. I think, because of the time and the smoke, it does count. Not sure everyone agrees. @kaszeta have a view on Hawaiian BBQ?

The New England Clam Bake doesn't count as it is using steam rather than smoke.

St Louis, in Missouri, has some BBQ features that are unique. Including pig snouts.

There are venerable BBQ joints in Chicago that defy direct classification.

There are US/Mexico border dishes drawing heavily from Mexican cuisine that can likely be considered BBQ, such as cabrito.

My brother, @kaszeta the bacon photographer (yes) has a great foodie blog where he has many examples of much of this genre. https://offbeateats.org/ 

By which I mean the whole thing, not that cabrito bit.

Then there is this Baltimore-area thing called "pit beef" which I think does NOT qualify, even though it is objectively quite good. It uses charcoal, not wood smoke.

I would say that, having had exemplars of pretty much all this stuff (not the Luau, that's the only one of the 50 states I have not been to), it's folly to say which is best and which isn't.

Within each category there are good examples, there are authentic examples, often but not ALWAYS, the same thing. There are also poor examples and chain/institutional examples that lay in the mediocre middle, as with any cuisine.

Now, speaking of food, I am hungry and my long-suffering wife has been pot-roasting a guinea fowl, no doubt revenge for my roasted John Dory last night. End thread. Bye!