An Etymological Dictionary of the German Language/Kanker
Kanker (1.), m., ‘spider’ (MidG.), from the equiv. MidHG. kanker (rare), m. The derivation of the word from Lat. cancer, ‘crab’, is, for no other reason than the meaning, impossible. It seems to be based upon an OTeut. vb. ‘to weave, spin.’ This is indicated by the OIc. kǫngulváfa, kǫngurváfa, ‘spider’; AS. 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 prim. Teut. stem kang, ‘to spin,’ which in its graded form appears in ModHG. Kunkel. his stem has been preserved in the non-Teut. languages only in a Finn. loan-word; comp. Finn. kangas, ‘web’ (Goth. *kaggs).
Kanker (2.), m., ‘canker,’ from OHG. chanchar, cancur; comp. AS. cancer, E. canker. Probably OHG. chanchur is a real Teut. word from an unpermutated gongro-; comp. Gr. γόγγρος, ‘an excrescence on trees,’ γάγγραινα, ‘gangrene.’ Perhaps a genuinely Teut. term has been blended with a foreign word (Lat. cancer, Fr. chancre).