An Etymological Dictionary of the German Language/Annotated/Bug
Bug, masculine, ‘bend, flexure, hock, bow (of a ship),’ from Middle High German buoc(g), Old High German buog, masculine, ‘upper joint of the arm, shoulder, upper joint of the leg, hin, hock’; compare Dutch boeg, ‘ship’s bow,’ Anglo-Saxon bôg, bôh, ‘armus, ramus,’ English bough (‘the joint of a tree,’ as it were). The Gothic word may have been *bôgus (from pre-Teutonic bhâghú-s); compare Sanscrit bâhus (for bhâghú-s), ‘arm, fore-arm, fore-feet,’ also Greek πᾶχυς, πῆχυς (for φᾶχυς), ‘elbow, fore-arm, bend of the arm,’ Armenian bazuk, ‘arm.’ On account of the Aryan base bhâghú-s the derivation of Modern High German Bug from biegen (root bug, pre-Teutonic bhuk), is impossible. The ancient terms for parts of the body, such as Arm, Bug, Herz, Nase, Niere, &c., are based upon obscure roots, of which we find no further trace anywhere; they belong, in fact, to the most primitive vocabulary of Aryan speech. —