Turnip is a root describes as:

Turnip root is a napiform shape because of the top-heavy appearance. It is a modified taproot, which is broad and swollen at the top, but then suddenly tapers to a slim, tail-like point at the bottom. This swelling is for the storage of reserve food materials.

• Fusiform: spindle-shaped, thicker in the middle and tapering at both ends. This is characteristic of radishes.
• Conical: cone-shaped, widest at the base and then tapering to the top. This is characteristic of carrots.
• Tuberous: thick and fleshy but without a definite shape or symmetry. This is characteristic of the sweet potato or the Mirabilis jalapa (four o'clock plant).