Three-base hit (6)
I believe the answer is:
triple
I believe this is a double definition.
'three' is the first definition.
(thesaurus)
'base hit' is the second definition.
(I know that triple is a type of base hit)
(Other definitions for triple that I've seen before include "Three times" , "involving several parties" , "Threefold, treble" , "In three parts" , "make much longer" .)