Instead of an American error (my original hypothesis), it looks more like a case of simple reasonable linguistic divergence based on the changing nature of menus over the last century.
First of all, the big (Collins-Robert) dictionary added nothing much, except to say that the translation of `entrée'<BrE> to French is `entrée', and vice versa, whereas the translation of `main' <BrE> to French is `plat prinicpal' (which is what I thought I remembered, but which wasn't included in the little dictionary, which, you will recall, said `plat de résistance'). Neither dictionary gave a translation from the American `entrée' to French, but we can assume that it would be `plat principal'.
However: The traditional French menu, (according to Larousse, and to an 1895 American cookbook I own) went something like:
What I reckon happened, was that as the necessity of the main (rôti == roast (usually fowl in France)) course waned (more slowly, I suspect, in NZ, OZ and Britain than in the US), the entrée (which can cover a variety of dishes which would be considered mains now (but then, so would some of the hors d'oeuvres and final courses)) moved towards the beginning of the meal in <BrE>, <NZE> <AusE> and <Fr>, and towards the end of the (truncated) mean in <AmE>.
Since a modern (formal) (western of course, chinese menus put soup last, for example) menu goes something more like:
the English useage bears more resemblance to the traditional one, in terms of the formal/social/ritual aspects of hosting a dinner, whereas, since modern mains are rarely roasts, the American useage bears more resemblance to the food which was traditionally served for this course. Since the American cookbook I referred to (The Table, (2nd ed) 1895) followed the formal, old fashioned, French usage, it is clear that the divergence happened after that date. Michael (whose mind is now at rest on this matter, unless further culinary archeology by others upsets this theory). ------- OK. Here is what the 1989 edition of the Oxford English Dictionary (the definition of the British English lexicon) has to say:`Entrée' - [...] 2. Cookery. A `made dish', served between the dish and the joint. also attrib., as entrée dish (Littré explains entrées as `mets qui se servent au commencement du repas' [dishes which are served at the start of a meal]).
And here is what Robert [a multivolume French (not French-English) dictionary, though not as large as the OED] has to say:
Original:
entrée n.f. (XIIe s.; de entrer) - Specialt. Cuis. Mets qui se sert a l'entrée, au commencement du répas, après de pôtage ou après les hors-d'oeuvre. `l'entrée précede le rôti. On distingue les entrées de boucherie (boeuf, veau, mouton), de porc, de volailles et de gibier, de poisson, les entrées froides (pâtes froides, viandes froides ...), des entrées chaudes de four (vol-au-vent, bouchées, timbales, souffles...). Repas d'apparat à deux, trois entrées.'
My Translation:
entrée, noun, feminine (XII century; from `to enter') - Cookery. Dishes which are served `at the entrée', at the beginning of a meal, after soup, or after the hors-d'oeuvre. `The entrée precedes the roast. We distinguish between entrées of butchered meat (*1) (beef, veal, mutton), pork, fowl and game, fish, cold entrées (cold pates, cold meats [cold cuts in <AmE>], hot oven-prepared entrées (vol-au-vents, savouries(*2), timbales, souffles). A ceremonial dinner with two or three entrées'.
*1 French distinguishes between classes of meats in a slightly different way than English. In particular, there are special butchers for pork products (and horse, although that is not relevant here)).
*2 Literally `mouthfuls', my guess is that savouries is the right translation. I don't know what Americans call these.
[...] The plates translate into large (main course at dinner), medium (breakfast, luncheon, fish and another early course whose name, entree, has been wickedly stolen by restaurants to refer to the main course; as well as, on the small side of medium, salad, dessert) and small (bread and butter, fruit, tea). [...]witbrock@cs.cmu.edu -- emmendments, ammendments and expansions welcome