The Collaborative International Dictionary of English v.0.48:
Thimbleful \Thim"ble*ful\, n.; pl. Thimblefuls. As much as a thimble will hold; a very small quantity. [1913 Webster] For a thimbleful of golf, a thimbleful of love. --Dryden. [1913 Webster]WordNet (r) 3.0 (2006):
thimbleful n 1: as much as a thimble will hold [syn: thimble, thimbleful]