where does the term dead end come from
Dead end (street) The expression cul-de-sac comes from French, where it originally meant "bottom of the sack".[44] It was first used in English in anatomy (since 1738). It was used for dead-end streets since 1800 in English (since the 14th century in French).[45] The often heard erroneous folk etymology "arse/ass [buttocks] of the sack" is based on the modern meaning of cul in French, Catalan, and Occitan, but cul doesn't have that meaning in cul-de-sac, which is still used to refer to dead ends in modern French although the terms impasse and voie sans issue are more common in modern French.
Dead ringer (idiom) Dead ringer is an idiom in English. It means "an exact duplicate" and derives from 19th-century horse-racing slang for a horse presented "under a false name and pedigree"; "ringer" was a late nineteenth-century term for a duplicate, usually with implications of dishonesty, and "dead" in this case means "precise", as in "dead centre".[1]