Definition of thumb-indexed in US English:

thumb-indexed

adjective

  • See thumb index

    • ‘It is a vintage 1958 King James Version, gold-leafed, thumb-indexed and equipped with an extensive directory of useful topics.’
    • ‘In grade school, I used an old thumb-indexed concise dictionary that was spiral bound.’
    • ‘The book is also thumb-indexed, which is nice, but I don't necessarily need it.’