shackle

From Middle English shakel, schakkyl, schakle (“a fetter, shackle; coupling used to connect a plough or wagon to a draft chain”), from Old English sċacul, sċeacel, sċeacul (“fetter, shackle”), from Proto-West Germanic skakul, from Proto-Germanic skakulaz (“shackle”), possibly from skakaną (“to shake; to swing; to escape”), from Proto-Indo-European skeg-, skek- (“to shake; to stir”). However, this is doubted by the Oxford English Dictionary because skeg-, *skek- lack the meaning of attaching or fastening. Etymology 1 sense 3 (“length of cable or chain equal to 12½ or 15 fathoms”) derives from the original distance between two shackles (etymology 1 sense 1.1.3) connecting lengths of cable or chain together. Cognates * Danish skagle (“carriage trace”) * Dutch schakel (“clasp; link; shackle”) * German Schäckel (“shackle”) * Icelandic skökull (“carriage pole”) * Swedish skakel (“loose shaft of a carriage”)

From Middle English schakelen, schakkylen (“(also figurative) to put (someone) in shackles; to protect (legs) with greaves”), from shakel, schakkyl, schakle (noun) (see etymology 1) + -en (suffix forming the infinitives of verbs).

From shack (“variant of shake”), shake (verb) + -le (suffix forming agent nouns; frequentative suffix forming verbs).