early 14c., "to bear or convey, take along or transport," from Anglo-French carier "to transport in a vehicle" or Old North French carrier "to cart, carry" (Modern French charrier), from Gallo-Roman *carrizare, from Late Latin carricare, from Latin carrum originally "two-wheeled Celtic war chariot," from Gaulish (Celtic) karros, from PIE *krsos, from root *kers- "to run."
Meaning "take by force, gain by effort" is from 1580s. Sense of "gain victory, bear to a successful conclusion" is from 1610s; specifically in reference to elections from 1848, American English. Meaning "to conduct, manage" (often with an indefinite it) is from 1580s. Meaning "bear up and support" is from 1560s. Commercial sense of "keep in stock" is from 1848. In reference to mathematical operations from 1798. Of sound, "to be heard at a distance" by 1858.
To carry out "conduct to completion" is from c. 1600. To carry it off "brazen a thing out" is from 1704; carried off as a euphemism for "killed" is from 1670s. To be carried (away) in the figurative sense "transported, having the attention fully absorbed" is from 1560s. Carrying capacity is attested from 1836. Carry-castle (1590s) was an old descriptive term for an elephant.
late 14c., metathesis of Old English þurh, from Proto-Germanic *thurx (source also of Old Saxon thuru, Old Frisian thruch, Middle Dutch dore, Dutch door, Old High German thuruh, German durch, Gothic þairh "through"), from PIE root *tere- (2) "to cross over, pass through, overcome." Not clearly differentiated from thorough until early Modern English. Spelling thro was common 15c.-18c. Reformed spelling thru (1839) is mainly American English.
1950, from the verbal phrase, "see things on the other side of" (c. 1400); see see (v.) + through (adv.). The verbal phrase see through often is figurative, "perceive the real character of, detect imposture." To see (something) through "continue with until the end" is by 1828 (to see (something) out in the same sense is from 1782).