Rutabaga has many national and regional names. Rutabaga is the common North American term for the plant. This comes from the old Swedish dialectal word rotabagge, from rot (root) + bagge (short, stumpy object; probably related to bag). In the U.S., the plant is also known as Swedish turnip or yellow turnip. The term swede is used instead of rutabaga in many Commonwealth Nations, including much of England, Australia, and New Zealand. The name turnip is also used in parts of Northern and Midland England, the West Country (particularly Cornwall), Ireland, the Isle of Man, Manitoba, Ontario and Atlantic Canada. In Wales, according to region it is variously known as maip, rwden, erfin, swedsen or swejen in Welsh and as swede or turnip in English. In Scotland, it is known as turnip, and in Scots as tumshie or neep (from Old English næp, Latin napus). Some areas of south east Scotland, such as Berwickshire and Roxburghshire, still use the term baigie, possibly a derivative of the original Swedish rutabaga. The term turnip is also used for the white turnip (Brassica rapa ssp rapa). Some will also refer to both swede and (white) turnip as just turnip (this word is also derived from næp). In North-East England, turnips and swedes are colloquially called snadgers, snaggers (archaic) or narkies. Rutabaga is also known as a ‘moot’ in the Isle of Man and the Manx Gaelic for turnip is ‘napin’.
Its common name in Sweden is kålrot (literally "cabbage/kale root"). Similarly, in Denmark it is known as kålroe and kålrabi, while in Norway it is known as kålrabi or kålrot and in Estonia as kaalikas. In Denmark and Norway, kålrabi is sometimes confused with Swedish kålrabbi (kohlrabi). The Finnish term is lanttu. The Romanian term is nap. Rutabaga is known by many different regional names in German, of which Kohlrübe and Steckrübe are the most widespread and most commonly used in lists of ingredients.
The first known printed reference to the rutabaga comes from the Swiss botanist Gaspard Bauhin in 1620, where he notes that it was growing wild in Sweden. It is often considered to have originated in Scandinavia or Russia. It is said to have been widely introduced to Britain around 1800, but it was recorded as being present in the royal gardens in England as early as 1669 and was described in France in 1700. It was asserted by Sir John Sinclair in his Husbandry of Scotland to have been introduced to Scotland around 1781–1782. An article on the topic in The Gardeners' Chronicle suggests that the rutabaga was then introduced more widely to England in 1790. Introduction to North America came in the early 19th century with reports of rutabaga crops in Illinois as early as 1817.
Rutabaga has a complex taxonomic history. The earliest account comes from the Swiss botanist Gaspard Bauhin, who wrote about it in his 1620 Prodromus. Brassica napobrassica was first validly published by Carl Linnaeus in his 1753 work Species Plantarum as a variety of B. oleracea: B. oleracea var. napobrassica. It has since been moved to other taxa as a variety, subspecies, or elevated to species rank. In 1768, a Scottish botanist elevated Linnaeus' variety to species rank as Brassica napobrassica in The Gardeners Dictionary, which is the currently accepted name.
Rutabaga has a chromosome number of 2n = 38. It originated from a cross between turnip (Brassica rapa) and Brassica oleracea. The resulting cross then doubled its chromosomes, becoming an allopolyploid. This relationship was first published by Woo Jang-choon in 1935 and is known as the Triangle of U.