1520s, "to recount, tell," from French relater "refer, report" (14c.) and directly from Latin relatus, used as past participle of referre "bring back, bear back" (see refer), from re- "back, again" + lātus "borne, carried" (see oblate (n.)).
The meaning "stand in some relation; have reference or respect" is from 1640s; transitive sense of "bring (something) into relation with (something else)" is from 1690s. Meaning "to establish a relation between" is from 1771. Sense of "to feel connected or sympathetic to" is attested from 1950, originally in psychology jargon. Related: Related; relating.
c. 1600, "recited, narrated;" 1702, "connected by blood or marriage," past-participle adjective from relate (v.) in various senses. Related: Relatedness.
"informer," with a specialized sense in law, c. 1600, from Latin relator, agent noun; see relate. Related: Relatrix.
c. 1300, relacioun, "relationship, connection, correspondence;" late 14c. as "act of telling or relating in words," from Anglo-French relacioun, Old French relacion "report, connection" (14c.) and directly from Latin relationem (nominative relatio) "a bringing back, restoring; a report, proposition," from relatus (see relate).
The meaning "person related by blood or marriage" is attested from c. 1500. The phrase no relation "not in the same family," used in differentiating persons with the same surname, is attested by 1930.
"tell or recite in detail, relate the particulars or incidents of," 1748, a back-formation from narration or else from Latin narratus, past participle of narrare "to tell, relate, recount," from PIE root *gno- "to know." "Richardson and Johnson call it Scottish" [OED], a stigma which kept it from general use until 19c. A few mid-17c. instances are traceable to Spanish narrar. Related: Narrated; narrating.