Definitions for "doubled"
Keywords:  twice, twofold, great, dose, rendered
rendered twice as great or twice as many.
twice as great or many; "ate a double portion"; "the dose is doubled"; "a twofold increase"
The lining of a mantling or chapeau
When a single line track is extended to one track in each direction, it is said to have been "Doubled".
Keywords:  traced, knot, distinct, cord, parallel
doubled knot has it's structure traced by two parallel cords instead of the usual one, although the parallel cord need not be a separate and distinct cord.
Keywords:  folded, sheets, paper, two
folded in two; as, doubled sheets of paper.