(Jimmy of the Clue Crew shows a plant diagram on the monitor.)  Similar to a root, it's the botanical term for a thick, horizontal underground stem from which shoots develop into new plants
It is in this broad sense that the term is used in Inventions and Inventors, 
the .... And that is a facet to inventions that needs emphasizing, because it shows 
that ..... Edison began experiments aimed at developing a rechargeable battery 
with... [DOC] [TLE] subsurface water storage: Topics by WorldWideScience.org [PAR] New methods and technologies for energy storage are required for the transition 
to ...