Catechu ( or ) is an extract of acacia trees used variously as a food additive, astringent, tannin, and dye. It is extracted from several species of
Acacia, but especially
Senegalia catechu (
Acacia catechu), by boiling the wood in water and evaporating the resulting brew. It is also known as
cutch,
black cutch,
cachou,
cashoo,
khoyer,
terra Japonica, or
Japan earth, and also
katha in Hindi,
kaath in Marathi,
khoyer in
Assamese and
Bengali, and
kachu in Malay (hence the Latinized
Acacia catechu chosen as the
Linnaean taxonomy name of the type-species Acacia plant which provides the extract).