Source : Webster's Revised Unabridged Dictionary (1913)

Tablespoonful \Ta"ble*spoon`ful\, n.; pl. {Tablespoonfuls}.
   As much as a tablespoon will hold; enough to fill a
   tablespoon. It is usually reckoned as one half of a fluid
   ounce, or four fluid drams.

Source : WordNet®

tablespoonful
     n : as much as a tablespoon will hold [syn: {tablespoon}]