What's the difference between earthnut and pignut?

Earthnut

Definition:

• (n.) A name given to various roots, tubers, or pods grown under or on the ground
• (n.) The esculent tubers of the umbelliferous plants Bunium flexuosum and Carum Bulbocastanum.
• (n.) The peanut. See Peanut.

Example Sentences:

Pignut

Definition:

• (n.) See Groundnut (d).
• (n.) The bitter-flavored nut of a species of hickory (Carya glabra, / porcina); also, the tree itself.

Example Sentences: