Valium

google

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1960s: of unknown origin.

wiktionary

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Marketing coinage. (This etymology is missing or incomplete. Please add to it, or discuss it at the Etymology scriptorium.)

etymonline

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Valium (n.)

1961, proprietary name (Hoffmann-La Roche Inc., Nutley, N.J.) of diazepam (reg. U.S.), of unknown origin.