An Etymological Dictionary of the German Language/Annotated/frohn
frohn, adjective, ‘lordly, holy,’ now only preserved as the first component in archaic compounds; from Middle High German vrôn, adjective, ‘relating to the master or lord, sacred.’ In Old High German there appears instead of an adjective *frôn a petrified form frôno, ‘magnificent, divine, sacred,’ which is properly a genitive plural of frô, ‘lord’ (used only in the vocative). In Middle High German vrôn appears in numerous compounds for the temporal lord, as well as for the κύριος, ‘the lord,’ κατ’ ἐξοχήν, ‘Christ’; compare Middle High German vrônlîchnam, masculine, ‘Christ’s body, the host,’ Modern High German Frohnleihnam; Middle High German vrônkriuze, Old High German daz frôno chrûzi, ‘the cross of Christ’; Middle High German vrônalter, ‘high altar,’ &c.; also vrônhof, ‘mansion,’ vrônwalt, ‘a wood belonging to the lord,’ vrônrëht, ‘public right.’ Modern High German retained Frohndienst, from Middle High German vrôndienst; see fröhnen. As to Old High German frô,‘O lord,’ stress must be laid on its correspondence to Anglo-Saxon freá, ‘lord,’ as well as Old Saxon frao. Gothic has a form with j, frauja, masculine (Anglo-Saxon frêgea), ‘lord,’ which is seen in High German in the feminine forms Old High German frouwa, Middle High German vrouwe, Gothic *fraujô, With these some connect in Scandinavian the names of the deities Freyr and Freyja. Whether the stem fraun-, for frawun- and fraujan-, in the sense of ‘gracious, friendly,’ is allied to the adjective froh, ‘glad,’ remains to be proved. Compare Frau.
frohn, Old High German frô and Gothic frauja, 'lord,' are cognate with Sanscrit pûrva, pûrvya, and Old Slovenian prǔvǔ, 'first' (Old High German frô, from frawan, equivalent to pṛwo-, Gothic frauja, from frawjan, equivalent to pṛwyo; Sanscrit pûrvya, as an attribute of the gods, corresponds to Old Icelandic Freyr (compare Gott).