Connubial \kuh-NOO-bee-ul\ or \kun-NYOO-bee-ul\ , adjective;
1. Of or pertaining to marriage, or the marriage state; conjugal; nuptial
This word dates to the 1650's from Latin connubialis, a variant of conubialis ("pertaining to wedlock") from conubium ("marriage"), which is a combination of com- + nubere ("together" + "to wed").
Nubere is the forebear of nubile, which originally meant "marriageable" in reference to a woman. The meaning "young and sexually attractive" is first attested in 1973.
Today's word and the first definition were both taken from Dictionary.com's 'Word of the Day' for Tuesday, May 17
Etymologies come from the Oxford English Dictionary and/or Etymonline.com