Natural oil with a distinctive scent secreted by
the glands of certain aromatic plants. Terpenes
are the main constituents.
Essential oils are extracted
from plants by steam distillation, extraction with
cold neutral fats or solvents (e.g. alcohol) or pressing
and used in perfumes, flavourings and medicine; e.g.,
citrus oils, flower oils (e.g. rose, jasmine) and
oil of cloves.