oleander
Concise Oxford English Dictionary © 2008 Oxford University Press:
oleander /ˌəʊlɪˈandə/
▶noun a poisonous evergreen shrub grown in warm countries for its clusters of white, pink, or red flowers. [Nerium oleander.]
– origin C16: from med. L., of unknown ultimate origin.
'oleander' also found in these Oxford entries:

