Construction built by social insects (3,4)
(Other definitions for ant hill that I've seen before include "Mound of insects" , "Termite mound" , "Insects' construction" , "Queen's building" , "Insect colony" .)
(Other definitions for anthill that I've seen before include "Home to thousands" , "Mound of insects" , "Mountain (of insects)" , "Many a worker here" , "There's much work to be done here" .)