Stonehenge (n.)
"celebrated stone circle on Salisbury Plain" [OED], early 12c., Stanenges, literally "stone gallows," perhaps so called from fancied resemblance to old-style gallows with two posts; from stone (n.) + second element related to hang (v.).
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.
The thing itself is from a time immemorial to the earliest Germanic writings. An ancient common name for it was the Giant's Dance. In Middle English a stonehenge also was a device for clamping stones together.
also from early 12c.