RhymeZone: blackstrap definitions

Definitions of blackstrap:

noun: The dark, viscous molasses remaining after maximum extraction of sugar from raw sugar cane, used in manufacturing and cattle feed.
noun: (obsolete) A mixture of spirituous liquor (usually rum) and molasses.
noun: (obsolete, nautical, slang) Bad port wine; any common wine of the Mediterranean.

(Definitions from Wiktionary)