1. In birds, the thin-walled enlargement of
the digestive tract between the oesophagus
and stomach. It is an effective storage organ
especially in seed-eating birds; a pigeon's
crop can hold about 500 cereal grains.
Digestion begins in the crop, by the
moisturizing of food. A crop also occurs in
insects and annelid worms.

2. A plant grown for human use. Over 80 crops
are grown worldwide, providing people with
the majority of their food, and supplying
fibres, rubber, pharmaceuticals,
dyes, and other materials. There are four
main groups of crops: food crops provide the
bulk of people's food worldwide. The major
types are cereals, roots, pulses, vegetables,
fruits, oil crops, tree nuts, sugar,
beverages, and spices. Cereals make the
largest contribution to human nutrition.
forage crops are crops like grass, clover,
and kale, which are grown to feed livestock.
Forage crops cover a greater area of the
world than food crops. Grass, which dominates
this group, is the world's most abundant
crop, though much of it is still in an
unimproved state. fibre crops produce
vegetable fibres. Temperate areas produce
flax and hemp, but the most valuable fibre
crops are cotton, jute, and sisal, which are
grown mostly in the tropics. Cotton dominates
fibre crop production. miscellaneous crops
include tobacco, rubber, ornamental flowers,
and plants which produce perfume,
pharmaceuticals, and dye. See also catch
crop.