from
The Collaborative International Dictionary of English v.0.48
Locust tree \Lo"cust tree`\n. [Etymol. uncertain.] (Bot.)
A large North American tree of the genus {Robinia} ({Robinia
Pseudacacia}), producing large slender racemes of white,
fragrant, papilionaceous flowers, and often cultivated as an
ornamental tree. In England it is called {acacia}.
[1913 Webster]
Note: The name is also applied to other trees of different
genera, especially to those of the genus {Hymen[ae]a},
of which {Hymen[ae]a Courbaril} is a lofty, spreading
tree of South America; also to the carob tree
({Ceratonia siliqua}), a tree growing in the
Mediterranean region.
[1913 Webster]
{Honey locust tree} (Bot.), a tree of the genus {Gleditschia}
) {Gleditschia triacanthus}), having pinnate leaves and
strong branching thorns; -- so called from a sweet pulp
found between the seeds in the pods. Called also simply
{honey locust}.
{Water locust tree} (Bot.), a small swamp tree ({Gleditschia
monosperma}), of the Southern United States.
[1913 Webster]