also short-bread, "flat cake made of flour, butter, and sugar in proportion to make it 'short' (crumbly) when baked," 1755, from short (see shortening) + bread (n.).
Entries linking to shortbread
shortening n.
1540s, "action of making short," verbal noun from shorten.
The meaning "butter or other fat or oil used in baking" (by 1796) is from shorten in the cookery sense "make crumbly," attested by 1733. This is from short (adj.) in a secondary sense in reference to food, "friable, easily crumbled," attested by early 15c. in cookery books.
Hence short pastry, in full shortcrust pastry, that to which lard or butter has been added to make it soft and flaky. This also is the short in shortbread and shortcake. Also shortening bread (by 1884), a U.S. Southern specialty.
Short (adj.) as "easily crumbled" also has been applied to things other than food, and this use of it perhaps implies "having short fibers," as materials with short fibers fall apart more easily (e.g. short-staple cotton).
bread n.
"kind of food made from flour or the meal of some grain, kneaded into a dough, fermented, and baked," Old English bread "bit, crumb, morsel; bread," cognate with Old Norse brauð, Danish brød, Old Frisian brad, Middle Dutch brot, Dutch brood, German Brot.
According to one theory [Watkins, etc.] from Proto-Germanic *brautham, from PIE root *bhreu- "to boil, bubble, effervesce, burn," in reference to the leavening. But OED argues at some length for the basic sense being not "cooked food" but "piece of food," and the Old English word deriving from a Proto-Germanic *braudsmon- "fragments, bits" (cognate with Old High German brosma "crumb," Old English breotan "to break in pieces") and being related to the root of break (v.). It cites Slovenian kruh "bread," literally "a piece."
Either way, by c. 1200 it had replaced the usual Old English word for "bread," which was hlaf (see loaf (n.)).
The extended sense of "food, sustenance in general" (late 12c.) is perhaps via the Lord's Prayer. The slang meaning "money" dates from 1940s, but compare breadwinner, and bread as "one's livelihood" dates to 1719. Bread and circuses (1914) is from Latin, in reference to food and entertainment provided by the government to keep the populace content. "Duas tantum res anxius optat, Panem et circenses" [Juvenal, Sat. x.80].