English Etymology Variant of Oates. Proper noun Oatis (plural Oatises) A surname. Statistics According to the 2010 United States Census, Oatis is the 25486th most common surname in the United States, belonging to 970 individuals. Oatis is most common among Black/African American (75.57%) and White (18.97%) individuals. Further reading Hanks, Patrick, editor (2003), “Oatis”, in Dictionary of American Family Names, volume 3, New York: Oxford University Press, →ISBN. Anagrams Ostia, ostia, TOISA, Saito, Toias, stoai, IOTAs, taosi, iotas, staioWikiwand - on Seamless Wikipedia browsing. On steroids.