The turnip or white turnip (Brassica rapa subsp. rapa) is a root vegetable commonly grown in temperate climates worldwide for its white, fleshy taproot. The word turnip is a compound of tur- as in turned/rounded on a lathe and neep, derived from Latin napus, the word for the plant.

Small, tender varieties are grown for human consumption, while larger varieties are grown as feed for livestock. In the north of England, Scotland, Ireland, Cornwall and eastern Canada (Newfoundland and the Maritimes), turnip (or neep) often refers to rutabaga, a larger, yellow root vegetable in the same genus (Brassica) also known as swede (from "Swedish turnip").

More Info: en.wikipedia.org