leafcutter ant Syllabification: (leaf·cut·ter ant)Pronunciation: /ˈlēfˌkətər/Definition of leafcutter ant noun a tropical ant that cuts pieces from leaves and carries them back to the nest for use as a culture medium for growing food fungi. Genus Atta, family Formicidae leafcutter ant in other Oxford dictionaries Definition of leafcutter ant in the British & World English dictionary