jack oak in WordNet English dictionary

1. a common scrubby deciduous tree of central and southeastern United States having dark bark and broad three-lobed (club-shaped) leaves; tends to form dense thickets
   blackjack oak  blackjack  jack oak  Quercus marilandica 
   
2. small to medium deciduous oak of east central North America; leaves have sharply pointed lobes
   jack oak  northern pin oak  Quercus ellipsoidalis