"rectangular block of artificial stone (usually clay burned in a kiln) used as a building material," early 15c., from Old French briche "brick," which is probably from a Germanic source akin to Middle Dutch bricke "a tile," etymologically "a bit, a fragment, a piece broken off," from the verbal root of break (v.).
Of a brick-shaped loaf by 1735. Meaning "a good, honest fellow" is from 1840, probably on notion of squareness (as in fair and square), though in English brick and square when applied to persons generally are not meant as compliments. Brick wall in the figurative sense of "impenetrable barrier" is from 1886. Brick-and-mortar (adj.) as figurative of "physically real" is from 1865. To do something like a ton of bricks "vigorously" is from 1929 (earlier thousand of bricks, 1836), probably from the notion of how hard such a weight of them falls or hits.