agoraphobia UK /ˌæɡ.ə.ɹəˈfəʊ.bi.ə/US /ˌæɡ.ɚ.əˈfoʊ.bi.ə/ noun2 •The fear of wide open spaces, crowds, or uncontrolled social conditions. •(rare) An aversion to markets. formsagoraphobias