An Etymological Dictionary of the German Language/Grab
Grab, n., from the equiv. MidHG. grap(b), OHG. grab, n., ‘grave’; like Graben; m., ‘ditch, trench, sewer,’ from the equiv. MidHG. grabe, OHG. grabo, m.; allied to ModHG. graben, ‘to dig, engrave,’ from the equiv: MidHG. graben, OHG. graban, str. vb.; a common Teut. str. vb., corresponding to Goth. graban, AS. grafan, E. to grave, Du. graven (graf, ‘grave’); from a common Teut. root grab (pre-Teut. ghrabh), which is primit. allied to OSlov. grebą, ‘I dig, row,’ and grobŭ, ‘grave’; Gr. γράφω, ‘I scratch, write,’ has probably no connection with the word, Comp. Griffel, Grube, Gruft, grübeln.