What is the difference between a turnip and a radish?

They are separate genera and species from the same family, Brassicaceae, informally known as the mustards, mustard flowers, the crucifers, cruciferous vegetables or the cabbage family.

The family contains well-known species such as Brassica oleracea (broccoli, cabbage, cauliflower, kale, collards, Brussels sprouts, etc.), Brassica rapa (turnip, mizuna, napa cabbage, etc.), Brassica napus (canola, etc.), Raphanus sativus (common radish), Armoracia rusticana(horseradish), and many others.

A radish can range from the size of your thumb to very large. In the U.S., it is typically red with a white center, although other colors are available. A turnip is typically the size of a Golf ball up to the size of a softball and is typically white, especially the smaller ones, and may turn purple on top as it gets older.

The leaves of both radishes and turnips are edible in salads or cooked like collards.