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.
late 14c., mornere, "one who laments or grieves" (especially for the death of a friend or relation), agent noun from mourn (v.). Meaning "one hired to lament for the dead" is from 1690s.
"the secondary term of a relation, that to which something is related," 1640s, perhaps a back-formation from correlation or from correlate (adj.), from a Medieval Latin adjectival use of the Latin past participle.
linking or connecting verb (especially "be"), word which expresses relation between subject and predicate, 1640s, from Latin copula "that which binds, rope, band, bond" (see copulate). Related: Copular.
1670s, "to assume a position" (intransitive), from position (n.). Transitive sense of "place or put in relation to other objects," now the usual meaning, is recorded from 1817. Related: Positioned; positioning.
1650s, "a whole comprised of interconnected parts," from complex (adj.). Latin completus as a noun meant "a surrounding, embracing, connection, relation." Psychological sense of "connected group of repressed ideas" was established by C.G. Jung, 1907.