Avestan Hvare khshaeta is a compound in which hvar "Sun" has khshaeta "radiant" as a stock epithet. Avestan hvar derives from the Indo-Iranian root *svar "to shine," from which Vedic SanskritSurya - again "Sun" - also derives. In Middle Persian, Hvare khshaeta was contracted to Khwarshēd, continuing in New Persian as Khurshēd/Khorshīd. (cf. a similar contraction of Avestan Yima khshaeta as Jamshid).
The short seven-verse 6th Yasht is dedicated to Hvare-khshaeta, as is also the Avesta's litany to the Sun. The 11th day of the Zoroastrian calendar is dedicated to and is under the protection of Hvare-khshaeta. Although in tradition Hvare-khshaeta would eventually be eclipsed by Mithra as the divinity of the Sun (this is attributed to "late" syncretic influences, perhaps to a conflation with Akkadian Shamash), in scripture the Sun is still unambiguously the domain of Hvare-khshaeta and remains distinct from the divinity of "Covenant."