(d) (Math.) That factor of a quantity which when multiplied into itself
will produce that quantity; thus, 3 is a root of 9, because 3
multiplied into itself produces 9; 3 is the cube root of 27. (e) (Mus.)
The fundamental tone of any chord; the tone from whose harmonics, or
overtones, a chord is composed. Busby.
(f) The lowest place, position, or part. "Deep to the roots of hell."
Milton. "The roots of the mountains." Southey.