correlation (n.)youdaoicibaDictYouDict
1560s, from Middle French corrélation, from cor- "together" (see com-) + relation (see relation).
interrelation (n.)youdaoicibaDictYouDict
1841, from inter- + relation.
interrelationship (n.)youdaoicibaDictYouDict
also inter-relationship, 1841, from inter- + relationship.
relation (n.)youdaoicibaDictYouDict
late 14c., "connection, correspondence;" also "act of telling," from Anglo-French relacioun, Old French relacion "report, connection" (14c.), from Latin relationem (nominative relatio) "a bringing back, restoring; a report, proposition," from relatus (see relate). Meaning "person related by blood or marriage" first attested c. 1500. Stand-alone phrase no relation "not in the same family" is attested by 1930.
relational (adj.)youdaoicibaDictYouDict
1660s, from relation + -al (1).
relationship (n.)youdaoicibaDictYouDict
1640s, "sense or state of being related," from relation + -ship. Specifically of romantic or sexual relationships by 1944.