Or another way that the word is used; is to state that there are 2-sheets of material.
As an example: Warbonnet Blackbird 1.7oz DOUBLE.
(It has 2 layers of 1.7oz/sq. yard main material)
I ride a recumbent.
I like to HAM it up on the CW.
I use Linux.
I play go.
Of course I sleep in a hammock!