An Etymological Dictionary of the German Language/Mandel
Mandel (1.), ‘fifteen,’ ModHG. only; the other meaning, which appears in earlier ModHG., ‘shock of corn (of 15 sheaves),’ may be the older. The G. word cannot be etymologically explained. (MidLat. mandala, ‘15 articles,’ is met with even in the 13th cent.); its relation to Du. mand, E. maund, ‘basket,’ is obscure.
Mandel (2.), f., ‘almond,’ from the equiv. MidHG. mandel, OHG. mandala, f.; from Ital. mandola; corresponding lo MidLat. and Prov. amandola, Fr. amande (hence Du. amandel, E. almond). Gr. ἀμυγδάλη is usually regarded as the ultimate source of these cognates.