רד"ו, r’du, (numerical value) two hundred and ten years, the traditional time of the slavery in Egypt. Gen. R. s. 91 (ref. to רְדוּ, Gen. XLII, 2) בישרם … כמנין ר׳ he announced to them that they would live there in slavery two hundred and ten years, corresponding to the numerical value of רד"ו; Num. R. s. 13, end כנגד ר׳ שנים וכ׳ corresponding to the 210 years which Israel spent in Egypt.