My earlier ramblings on the "Mediterranean trinity" raised a number of questions, including: What is bread? Too lazy to do actual research, I turned to my favorite pastime, online amateur etymology. The English word originally meant a morsel of food; its etymology is instructive: Indo-European *bhreu-, to boil --> Germanic *braudam, cooked --> Old English bréad, a bit of food --> OE bréad, bread stricto sensu (this last stage by 1200, according to the OED, displacing hláf, loaf, the earlier word for bread). It is interesting that cognate derivatives include brew and ferment, which must go all the way back to an IE analogy between bubbling from boiling, and bubbling from fermentation, but this branch is unrelated to the word bread itself, which came directly from "cooked." Considering the restrictions the word was forced to undergo to get to its current meaning, it is strange that the OED [sub. req.] neglects the "food in general" sense, proceeding directly from OE "bits of food" to 2.a.:
A well-known article of food prepared by moistening, kneading, and baking meal or flour, generally with the addition of yeast or leaven.Contrast American Heritage:
2a. Food in general, regarded as necessary for sustaining life; b. Something that nourishes; sustenance.
It is easy to see how this happened: bread is literally the staff of life whether you use Oxford's 2a. definition or American Heritage's. So pain B. is: "Toute espèce de nourriture indispensable à la vie" [cool TLF link thanks to languagehat]. This is etymologically explicit in all the Romance languages, derived from the Latin panis (from the IE root *pa-, to protect or feed): II. 1. Food in general. (The same is true in Hebrew, which I will leave alone for the moment). And a little Jesus takes the transf. to a whole new level [John 6:35]:
And Jesus said unto them, I am the bread of life: he that cometh to me shall never hunger; and he that believeth on me shall never thirst.
In any event, it does seem from the OED's cites that both bréad and hláf pretty specifically mean a loaf made from something (not necessarily grain) ground up and cooked (in some way -- I'm not certain that it had to be baked), whether leavened or not. I originally wanted to show that "bread" had another, narrower, general sense, in that it can also mean "polenta," which is just that same something ground up and boiled en masse but here the internet failed me. I'm not sure it can't be done, but it will be annoyingly painstaking.