Louis Sullivan louis·sul·li·van uncommon noun 1. United States architect known for his steel framed skyscrapers and for coining the phrase `form follows function'' (1856-1924) SynonymsSullivanLouis SullivanLouis Henry SullivanLouis Henri Sullivan Related words Broader terms architect WordNet 2.1 (Princeton University). WordNet 2.1 Copyright Princeton University. All rights reserved.