bluebonnet Syllabification: (blue·bonnet)Pronunciation: /ˈblo͞oˌbänit/Definition of bluebonnet noun a blue-flowered lupine, especially common in Texas. Genus Lupinus, family Leguminosae: several species, in particular the Texas bluebonnet (L. texensis) and the shy bluebonnet (L. subcarnosus) bluebonnet in other Oxford dictionaries Definition of bluebonnet in the British & World English dictionary