An Etymological Dictionary of the German Language/Annotated/Enke
Enke, masculine (unknown to Upper German), from the equivalent Middle High German ęnke, masculine, ‘farm servant, bind,’ Old High German ęncho, *ancheo (*ankjo), masculine, ‘servant’; corresponds only to Old Frisian inka and Low German enke, ‘servant.’ It is uncertain whether the word is primitively cognate with Latin ancilla, ‘maid-servant,’ since Latin c would be normally changed into Low German h or g; perhaps, however, it is based on the Aryan root ank or ang.