basal in WordNet English dictionary

1. especially of leaves; located at the base of a plant or stem; especially arising directly from the root or rootstock or a root-like stem
   "basal placentation"; "radical leaves"
   radical  basal 
   
2. serving as or forming a base
   "the painter applied a base coat followed by two finishing coats"
   basal  base 
   
3. of primary importance
   basal  primary