A bookmaker's record of bets and odds, or a book containing information for drug users; also slang for a racing form or betting guide.
Dope (information, or drugs in slang) + book. The term combines 'dope' (inside information) with book (record), emerging in gambling and underground culture.
Dopebook is a perfect example of how slang words can simultaneously mean 'inside information about horses' and 'guide to drugs'—they emerge from subcultures where dope means both valuable secrets and the substance itself.
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