"morally correct," Old English riht "just, good, fair, proper, fitting, straight," from Proto-Germanic *rekhtaz (cf. Old High German reht, German recht, Old Norse rettr, Gothic raihts), from PIE root *reg- "move in a straight line," also "to rule, to lead straight, to put right" (see regal; cf. Greek orektos "stretched out, upright;" Latin rectus "straight, right;" Old Persian rasta- "straight, right," aršta- "rectitude;" Old Irish recht "law;" Welsh rhaith, Breton reiz "just, righteous, wise").
Cf. slang straight "honest, morally upright," and Latin rectus "right," literally "straight," Lithuanian teisus "right, true," literally "straight." Greek dikaios "just" (in the moral and legal sense) is from dike "custom."
As an emphatic, meaning "you are right," it is recorded from 1580s; use as a question meaning "am I not right?" is from 1961. The sense in right whale is "justly entitled to the name." Phrase right off the bat is 1888, also hot from the bat (1888), probably a baseball metaphor, but cricket is possible as a source; there is an early citation from Australia (in an article about slang): "Well, it is a vice you'd better get rid of then. Refined conversation is a mark of culture. Let me hear that kid use slang again, and I'll give it to him right off the bat. I'll wipe up the floor with him. I'll ---" ["The Australian Journal," November 1888].
Right stuff "best human ingredients" is from 1848, popularized by Tom Wolfe's 1979 book about the first astronauts. Right on! as an exclamation of approval first recorded 1925 in black slang, popularized mid-1960s by Black Panther movement. Right of way is attested from 1768.
"opposite of left," early 12c., riht, from Old English riht, which did not have this sense but meant "good, proper, fitting, straight" (see right (adj.1)). The notion is of the right hand as the "correct" hand. The usual Old English word for this was swiþra, literally "stronger." "The history of words for 'right' and 'left' shows that they were used primarily with reference to the hands" [Buck]. Cf. similar sense evolution in Dutch recht, German recht "right (not left)," from Old High German reht, which meant only "straight, just."
The usual PIE root (*dek-) is represented by Latin dexter (see dexterity). Other derivations on a similar pattern to English right are French droit, from Latin directus "straight;" Lithuanian labas, literally "good;" and Slavic words (Bohemian pravy, Polish prawy, Russian pravyj) from Old Church Slavonic pravu, literally "straight," from PIE *pro-, from root *per- (1) "forward, through" (see per).
The political sense of "conservative" is first recorded 1794 (adj.), 1825 (n.), a translation of French Droit "the Right, Conservative Party" in the French National Assembly (1789; see left (adj.)).
Old English rihtan "to straighten, rule, set up," from riht (adj.); see right (adj.1). Cf. Old Norse retta "to straighten," German richten, Gothic garaihtjan. Related: Righted; righting.
Old English riht (West Saxon, Kentish), reht (Anglian), "that which is morally right," also "rule of conduct; law of a land;" also "what someone deserves; a just claim; a legal entitlement." Also "the right" (as opposed to the left), from the root of right (adj.1). From early 14c. as "a right action, a good deed." The phrase to rights "at once, straightway" is 1660s, from sense "in a proper manner" (Middle English).