ˈrīˌzōm noun
( -s )
Etymology: New Latin rhizoma, from Greek rhizōma mass of roots (of a tree), stem, race, from rhizoun to cause to strike root, from rhiza root — more at root
1. : a more or less elongate stem or branch of a plant that is often thickened or tuber-shaped as a result of deposits of reserve food material, is usually horizontal and underground, produces shoots above and roots below, and is distinguished from a true root in possessing buds, nodes, and usually scalelike leaves — called also rootstalk ; compare bulb 1, corm
2. : stolon 2