cargo n.

c. 1300, "wheeled vehicle," from Anglo-French carre, Old North French carre, from Vulgar Latin *carra, related to Latin carrum, carrus (plural carra), originally "two-wheeled Celtic war chariot," from Gaulish karros, a Celtic word (compare Old Irish and Welsh carr "cart, wagon," Breton karr "chariot"), from PIE *krsos, from root *kers- "to run." The Celtic-Latin word also made it into Greek, as karron "wagon with four wheels."

"From 16th to 19th c. chiefly poetic, with associations of dignity, solemnity, or splendour ..." [OED]. Used in U.S. by 1826 of railway freight carriages and of passenger coaches on a railway by 1830; by 1862 of streetcars or tramway cars. The extension to "automobile" is by 1896, but between 1831 to the first decade of 20c. the cars meant "railroad train." Car bomb is attested from 1972, in a Northern Ireland context. The Latin word also is the source of Italian and Spanish carro, French char.

c. 1200, "a load, a weight," from Old French charge "load, burden; imposition," from chargier "to load, to burden," from Late Latin carricare "to load a wagon or cart," from Latin carrus "two-wheeled wagon" (see car). A doublet of cargo.

The meaning "responsibility, burden" is from mid-14c. (as in take charge, late 14c.; in charge, 1510s), which progressed to "pecuniary burden, cost, burden of expense" (mid-15c.), and then to "price demanded for service or goods" (1510s). The meaning "anything committed to another's custody, care, or management" is from 1520s.

The legal sense of "accusation" is late 15c.; earlier "injunction, order" (late 14c.). The meaning "address delivered by a judge to a jury at the close of a trial" is from 1680s. The electrical sense is from 1767.

The slang meaning "thrill, kick" (American English) is from 1951. The meaning "quantity of powder required for one discharge of a firearm" is from 1650s. The military meaning "impetuous attack upon an enemy" is from 1560s; as an order or signal to make such an attack, 1640s.