Rapeseed is the seed of the rape or rapeseed plant, a member of the mustard family. Unfortunate associations with the name of this plant aside, rapeseed is actually a major crop in many nations of the world, with the seeds being one of the principal components of the crop, although some cultures also eat the stalks, leaves, and flowers of rapeseed. For those who find the common name “rape” a bit offputting, this plant is also known as oilseed, rapa, rapaseed, or Brassica napus, more formally.

As the name “oilseed” suggests, the seeds of this plant are very high in oil. They can be ground into nutritious meal used in animal fodder, or pressed for the oil, which can be used for human food or in the production of biodiesel. Rapeseed greens are also popular in Asia, where they are eaten like other members of the Brassica genus, in a variety of dishes. Like other Brassicas, the greens have a slightly peppery bite.

There are two main types of rapeseed oil. Industrial rapeseed oil is the sort used to produce fuels, lubricants, and so forth. Canola is a special cultivar of rapeseed used to produce food-grade oil. While Canola and rapeseed are technically the same species, the cultivars have some marked genetic differences. Most importantly, Canola, a contraction of Canadian Oilseed, Low-Acid, is low in erucic acid, a substance which is toxic to humans in large amounts.

The United States, Canada, India, China, Australia, and European Union all grow rapeseed, and visitors to farming regions in these areas of the world often note the fields of tall stalks and bright yellow flowers in the fall and winter. Many countries use genetically modified versions of the plant which have been specially designed to resist herbicides, with the goal of making farming easier. Some people have protested this, arguing that herbicide-resistant crops and genetic modification of crops have serious ethical implications which are not being addressed by the companies which develop them.

Rapeseed oil has both omega-6 and omega-3 fatty acids, leading some people to suggest that it is a very healthy oil. However, studies have also linked rapeseed oil with some health problems, which would indicate that a closer analysis of rapeseed oil for human consumption may be in order. Because rapeseed is often heavily treated so that it will not go rancid, some of the health benefits may be moot, thanks to the high temperatures and chemicals used in processing.

Incidentally, if you're wondering about the name, it's derived from the Latin rapum, which means “turnip,” and it has been used since the 14th century. In the other sense of the word, “rape” is derived from rapere, “to take by force,” and it dates to 1481.