An Etymological Dictionary of the German Language/Annotated/Ehe
Ehe, feminine, ‘marriage, wedlock, matrimony,’ from Middle High German ê, êwe, feminine, ‘customary right, justice, law, marriage,’ Old High German êwa, feminine, ‘law, marriage’; corresponds to Old Saxon êo, masculine, ‘law,’ Dutch echt, ‘marriage’ (from ê-haft, see echt), Anglo-Saxon œ̂, œ̂w, feminine, ‘law, marriage.’ These West Teutonic cognates aiwi- might be derived from aigwí-, aihwí-, and connected with Latin aequum (base aiqo-). To this there is no objection from the linguistic standpoint, for it is probable that the cognates similar in sound and signifying ‘time, eternity,’ are totally different from those just quoted; compare Gothic aiws, Old High German êwa, Anglo-Saxon œ̂, œ̂w, ‘time, eternity,’ which are allied to Latin aevum, aeternus, Greek αἰών, αἰεί; so too Sanscrit aỹas, ‘duration of life.’ Yet the first group might also perhaps be connected with Sanscrit êva, masculine, ‘progress, course, procedure, custom.’