Flax, a plant of the family Linaceae, cultivated both for its fiber, from which linen yarn and fabric are made, and for its nutritious seeds, called flaxseed or linseed, from which linseed oil is obtained.

Flaxseed comes from the flax plant, which belongs to the Linaceae plant family. The flax plant is a small, single-stemmed annual that grows to about 2 ft (0.6 m) tall and has grayish-green leaves and sky-blue flowers.