A biscuit is bread. According to Dictionary.com, the first definition of a biscuit is:
a kind of bread in small, soft cakes, raised with baking powder or soda, or sometimes with yeast; scone.
Biscuits are fluffy, flaky clouds of dough served with both breakfast and dinner. They have golden brown tops—heaped with butter of course—that pair perfectly with fried chicken, bacon and eggs, honey, gravy and more.
You would be hard-pressed to imagine a meal that wouldn't be improved by the presence of a warm, savory bread-based biscuit.
Outside of the U.S., the biscuit takes on a different meaning. A British biscuit, for example, is a thin cookie-like treat, usually served with tea or eaten as a snack. Biscuits should have a snap to them, rather than puff-up like pillowy bread.
Biscuits can come in all shapes and sizes, but they should all have a crunch. Digestive biscuits are beautiful chocolate wafers that you don't have to feel as bad about eating (it helps with digestion, right?), whereas Custard Creams biscuits are the ultimate sandwich indulgence. The Oxford English Dictionary even agrees, a biscuit should be more cookie-like than bread-like:
...the word biscuit comes originally from the Latin biscotum (panem), which means bread ‘twice baked’, which would explain the hard, crunchy quality of a British biscuit.