Oron (the stress is on the second syllable) was coined by one of the contest’s Internet participants, from the Hebrew word or, meaning “light,” plus the diminutive suffix –on, thus giving us “little light.” Besides sounding like “Uranus,” it must have seemed fitting to those who voted for it, because the seventh planet is indeed a faint presence in the sky. Shaḥak, the runner-up, is a literary Hebrew word for “sky” that goes back to the Bible and would have been closer to Uranus in meaning, though without any phonetic similarity.Philologos also notes that the other five planets that were known in antiquity already have Hebrew names and that Pluto is no longer technically a planet (too small). I think they should name Pluto Sheol anyway.
Rahav, the new Hebrew name for Neptune, also appears in the Bible, where it is the name of a mythological sea monster. In the Book of Job, for instance, we are told, “By His [God’s] power He stilled the sea; by His understanding He smote Rahav.” The Talmudic tractate of Bava Batra even refers to Rahav as “the lord of the sea” (sar shel yam), which makes this legendary creature a rough Hebrew parallel to the Roman sea god Neptune. Tarshish, which came in second, is the name of a distant but unidentified Mediterranean city or land mentioned many times in the Bible, sometimes in the metaphorical sense of “far over the sea.”
Background here.