A marijuana cigarette; joint (1960s+ Narcotics)
(also thumb a ride) To solicit rides along a highway by pointing with one's thumb in the direction one wishes to travel; hitchhike (1939+)
[narcotics sense fr the fact that one sucks the cigarette as a baby does its thumb]
From the thumbnail sketch to the many variations of a conceptual scheme, one eliminating the other, many decisions are arrived at.
Well, give me in a thumbnail sketch, something about Mr. Jitkoff's background.
Cummings' life is scarcely even a sketch; at most it is a thumbnail sketch.