I. ˈtünə noun
Usage: capitalized
Etymology: New Latin, from English toon (II)
: a small genus of Old World trees (family Meliaceae) closely related to Cedrela but having a short disk and completely winged seeds
II. noun
( -s )
Etymology: Mexican Spanish tuna
: a Mexican tree ( Castilloa elastica ) that is a minor source of rubber — compare caucho