root

The usually underground portion of a plant that lacks buds, leaves, or nodes and serves as support, draws minerals and water from the surrounding soil, and sometimes stores food.

Any of various other underground plant parts, especially an underground stem such as a rhizome, corm, or tuber.

The embedded part of an organ or structure such as a hair, tooth, or nerve, that serves as a base or support.

The bottom or supporting part of something.

The essential part or element; the basic core.