Mortonian UK /mɔːˈtəʊ.ni.ən/US /mɔɹˈtoʊ.ni.ən/ adjective2 •Of or relating to Samuel George Morton (1799–1851), American physician and natural scientist.This cranium is now in the Mortonian collection. — 1863 •Of or relating to John Maddison Morton (1811–1891), English playwright who specialised in one-act farces.