A pea is most commonly the small spherical seed or the seed-pod of the legume Pisum sativum.Each pod contains several peas. Although it is botanically a fruit, it is treated as a vegetable in cooking. The name is also used to describe other edible seeds from the Fabaceae such as the pigeon pea (Cajanus cajan), the cowpea (Vigna unguiculata), and the seeds from several species of Lathyrus.

P. sativum is an annual plant, with a life cycle of one year. It is a cool season crop grown in many parts of the world; planting can take place from winter through to early summer depending on location. The average pea weighs between 0.1 and 0.36 grams. The species is used as a fresh vegetable, frozen or canned, but is also grown to produce dry peas like the split pea. These varieties are typically called field peas.

The pea is a green, pod-shaped fruit, widely grown as a cool-season vegetable crop. The seeds may be planted as soon as the soil temperature reaches 10°C (50°F), with the plants growing best at temperatures of 13 to 18°C (55°F-65°F). They do not thrive in the summer heat of warmer temperate and lowland tropical climates but do grow well in cooler high altitude tropical areas. Many cultivars reach maturity about 60 days after planting. Generally, peas are to be grown outdoors during the winter, not in greenhouses. Peas grow best in slightly acidic, well-drained soils.

Peas have both low-growing and vining cultivars. The vining cultivars grow thin tendrils from leaves that coil around any available support and can climb to be 1-2 m high. A traditional approach to supporting climbing peas is to thrust branches pruned from trees or other woody plants upright into the soil, providing a lattice for the peas to climb. Branches used in this fashion are sometimes called pea brush. Metal fences, twine, or netting supported by a frame are used for the same purpose. In dense plantings, peas give each other some measure of mutual support.