WordNet sense 1 (small deciduous tree of eastern and central United States having dark green lyrate pinnatifid leaves and tough moisture-resistant wood used especially for fence posts):

post oak, box white oak, brash oak, Quercus stellata

WordNet sense 2 (medium-sized evergreen of southwestern United States and northwestern Mexico with oblong leathery often spiny-edged leaves):

canyon oak, canyon live oak, maul oak, Quercus chrysolepis