bougainvillea UK /ˌbuː.ɡənˈvɪl.ɪ.ə/US /ˌbu.ɡənˈvɪl.jə/ noun1 •Any of several South American flowering shrubs or lianas, of the genus Bougainvillea, having three showy, colorful bracts attached below each group of three inconspicuous flowers.He arrives bearing flowers as though he's come to court me. Tonight he brings me bougainvillea. It is always a surprise. — 1991 formsbougainvilleas