Linseed oil is a type of oil that is derived from the FLAX plant, also known as Linum usitatissimum. It is a natural source of omega-3 fatty acids and has been used for centuries in traditional medicine and as a cooking oil. It is also used in the production of paints, varnishes, and linoleum. The source of linseed oil is the FLAX plant, which is a member of the Linaceae family and is native to the Mediterranean region. The oil is extracted from the seeds of the FLAX plant and is then processed to produce linseed oil.