An Etymological Dictionary of the German Language/sengen
sengen, vb., ‘to singe, scorch, from MidHG. sęngen, ‘to singe, burn,’ lit. ‘to cause to singe or crackle’; a factitive of MidHG. and ModHG. singen, with a peculiar development of meaning, which is shared by the E. to singe, from AS. *sęnğęan.