early 12c., Stanenges, literally "stone gallows," perhaps so called from fancied resemblance to old-style gallows with two posts, with the second element related to the verb hang. Some antiquarians suggest the notion may be of "supported in the air, that which hangs in the air" (compare henge-clif for Latin præruptum), in reference to the lintel stones, but the order of the elements and the inflection is against this. An ancient name for it was the Giant's Dance.
<a href="https://www.etymonline.com/word/henge">Etymology of henge by etymonline</a>
Harper, D. (n.d.). Etymology of henge. Online Etymology Dictionary. Retrieved $(datetime), from https://www.etymonline.com/word/henge