Webster's Revised Unabridged Dictionary · 1913

Rosebay

Rosebay , noun

(a)
(Botany) the oleander.
(b)
(Botany) Any shrub of the genus Rhododendron.
(c)
(Botany) An herb (Epilobium spicatum) with showy purple flowers, common in Europe and North America; -- called also great willow herb. [Obsolete; United States]