"short cannon, ordnance piece short in proportion to the size of its bore," fired at a high angle and meant to secure a vertical fall of the projectile, 1620s, originally mortar-piece (1550s), from French mortier "short cannon," in Old French, "bowl for mixing or pounding" (see mortar (n.2)). So called for its shape.
"mixture of cement, material used (in building) for binding together stones or bricks," mid-13c., from Old French mortier "builder's mortar, plaster; bowl for mixing" (13c.) and directly from Latin mortarium "mortar, mixture of lime and sand," also "crushed drugs," which probably is the same word as mortarium "bowl for mixing or pounding" (see mortar (n.2)), with the sense transferred from the bowl to the material prepared in it. Dutch mortel, German Mörtel are from Latin or French.
"bowl for pounding, vessel in which substances are beaten to powder by means of a pestle," c. 1200, from Old French mortier "bowl; builder's mortar" and directly from Latin mortarium "bowl for mixing or pounding," also used of the material prepared in it, a word of unknown origin as it is impossible now to determine which sense was original. Watkins says probably from PIE root *mer- "to rub away, harm;" de Vaan finds this plausible. Late Old English had mortere, from the same Latin source, which might also be a source of the modern word. German Mörser also is from Latin.
also mortar-board, 1823, "square board used by masons to hold mortar for plastering," from mortar (n.1) + board (n.1). By 1854 in reference to the academic cap, probably so called because it resembles the mason's board. Earlier it was called a mortar cap (1680s) or simply morter (c. 1600), from French mortier.
"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.