Transferred use of the surname derived from the regional name for the district around Middlesbrough, so named from Old English clif ‘bank, slope’ (genitive clifa) + land ‘land’. Grover Cleveland (1837–1908) was the 22nd and 24th president of the U.S.; Cleveland is also the name of a city in Ohio: both of these may be factors influencing its use as a given name in the U.S.
Scottish and northern Irish: Anglicized form of Scottish Gaelic Mac an Aba(dh) ‘son of the abbot’. In Scotland, monasteries often had hereditary lay abbots, who were not bound by rules of celibacy. The McNabs seem to have originated at the monastery of St. Faolan in Strathfillan.