gardenia UK /ɡɑːˈdiːnjə/US /ɡɑɹˈdinjə/ noun2 •Any of various tropical evergreen small trees or shrubs, of the genus Gardenia, having glossy leaves and white flowers. •The flower of these plants.Heed remembered the baby-powder smell from the bowl of gardenias, their edges browning like toast. — 2003 formsgardenias