A ring fastened to the guard of a dagger or sword to protect the wielder's hand.

to get (a passing vehicle) to stop and give one a ride, signalling to the driver by holding out one's thumb (as a hitchhiker) / to disapprove or reject

plural of black thumb

A lack of skill in gardening; brown thumb. / (more generally) An inability to make animals or plants in one's care thrive. / A person with a black thumb.

plural of e-thumb

A drinking game in which one player puts their thumb on the table, or other surface. The last of the other players to put their thumb on it has to drink

present participle of thumb down

Of a book, having a thumb index.

A series of alphabetically marked or otherwise labelled semicircular cut-outs in the fore edge of a large reference book, encyclopaedia, Bible, etc., that allows quick access to various parts of the text.

plural of thumb index