thimble

Concise Oxford English Dictionary © 2008 Oxford University Press:
thimble/ˈθɪmbl/

▶noun

• 1 a metal or plastic cap with a closed end, worn to protect the finger and push the needle in sewing.

  ■ any short metal tube or ferrule.

• 2 Nautical a metal ring, concave on the outside, around which a loop of rope is spliced.

– derivatives
thimbleful noun (pl. thimblefuls).

– origin OE thȳmel ‘finger-stall’ (see thumb, -le1).