An Etymological Dictionary of the German Language/Annotated/Kanker
Kanker (1.), masculine, ‘spider’ (Middle German), from the equivalent Middle High German kanker (rare), masculine. The derivation of the word from Latin cancer, ‘crab’, is, for no other reason than the meaning, impossible. It seems to be based upon an Old Teutonic verb ‘to weave, spin.’ This is indicated by the Old Icelandic kǫngulváfa, kǫngurváfa, ‘spider’; Anglo-Saxon gongelwœ̂fre, ‘spider,’ must also be based upon a similar word; its apparent meaning, ‘the insect that weaves as it goes along,’ is probably due to a popular corruption of the obscure first component. We should thus get a primary Teutonic stem kang, ‘to spin,’ which in its graded form appears in Modern High German Kunkel. his stem has been preserved in the non-Teutonic languages only in a Finnish loan-word; compare Finnish kangas, ‘web’ (Gothic *kaggs).
Kanker (2.), masculine, ‘canker,’ from Old High German chanchar, cancur; compare Anglo-Saxon cancer, English canker. Probably Old High German chanchur is a real Teutonic word from an unpermutated gongro-; compare Greek γόγγρος, ‘an excrescence on trees,’ γάγγραινα, ‘gangrene.’ Perhaps a genuinely Teutonic term has been blended with a foreign word (Latin cancer, French chancre).