Hops are the flowers of the hop plant Humulus lupulus, a member of the Cannabaceae family of flowering plants. They are used primarily as a bittering, flavouring, and stability agent in beer, to which, in addition to bitterness, they impart floral, fruity, or citrus flavours and aromas. Hops are also used for various purposes in other beverages and herbal medicine. The hops plants have separate female and male plants, and only female plants are used for commercial production. The hop plant is a vigorous, climbing, herbaceous perennial, usually trained to grow up strings in a field called a hopfield, hop garden, or hop yard when grown commercially. Many different varieties of hops are grown by farmers around the world, with different types used for particular styles of beer.

Humulus lupulus, the common hop or hops, is a species of flowering plant in the hemp family Cannabaceae, native to West Asia, Europe and North America. It is a perennial, herbaceous climbing plant which sends up new shoots in early spring and dies back to a cold-hardy rhizome in autumn. It is dioecious.