The Collaborative International Dictionary of English v.0.48:
Wintergreen \Win"ter*green`\, n. (Bot.)
A plant which keeps its leaves green through the winter.
Note: In England, the name wintergreen is applied to the
species of Pyrola which in America are called
English wintergreen, and shin leaf (see Shin leaf,
under Shin.) In America, the name wintergreen is
given to Gaultheria procumbens, a low evergreen
aromatic plant with oval leaves clustered at the top of
a short stem, and bearing small white flowers followed
by red berries; -- called also checkerberry, and
sometimes, though improperly, partridge berry.
Chickweed wintergreen, a low perennial primulaceous herb
(Trientalis Americana); -- also called star flower.
Flowering wintergreen, a low plant (Polygala paucifolia)
with leaves somewhat like those of the wintergreen
(Gaultheria), and bearing a few showy, rose-purple
oil of wintergreen, An aromatic oil, consisting almost
entirely of methyl salicylate (CH3CO.O.C6H4.OH),
obtained by distillation of an extract of the wintergreen
(Gaultheria procumbens); it can also be obtained from
some other plants. It is used as a flavoring agent for
tooth powders and pastes, sometimes combined with menthol
or eucalyptus. It is called also oil of teaberry, oil
of partridgeberry, and oil of gaultheria.
Spotted wintergreen, a low evergreen plant (Chimaphila
maculata) with ovate, white-spotted leaves.
[1913 Webster + PJC]