SUN IN HEBREW: Philologos has the story in Hot, Rare and Missed. Excerpt:

Mr. Goldman’s query, however, has nothing to do with the calendar. What bothers him, rather, is, “Admittedly, it is more than a half century since I attended Hebrew school, but the Hebrew word for sun that I remember quite distinctly is shemesḥ” He wants to know why, when we bless the sun, we don’t say a birkat ha-shemesh rather than a birkat ha-ḥamah?

The answer to this is that shemesh and ḥamah are synonyms for “sun” in Hebrew. Both go back to biblical times, with one or the other preferred in different stages of Hebrew’s history. Shemesh, the Hebrew cognate of an ancient Semitic word (in Arabic, it is shams), was the everyday word in the period of the Bible, in which it occurs more than 120 times.

Ḥamah, on the other hand, can be found only five times in the Bible. Formed from ḥam, “hot,” so that its literal meaning is “the hot one,” ḥamah was a relatively rare epithet for the sun that was reserved for literary or oratorical occasions. ...

For the calendrical issue in question, see here.