D defs.my
Entry 1 sense Webster, 1913

Teaspoonful

/(-fụl)/ · Tea·spoon·ful · IPA /ˈtiːspuːnfəl/
01 n. As much as teaspoon will hold; enough to fill a teaspoon; -- usually reckoned at a fluid dram or one quarter of a tablespoonful. Approximat…
pl. Teaspoonfuls, Teaspoonsful ((-fụlz))
  1. 1.
    As much as teaspoon will hold; enough to fill a teaspoon; -- usually reckoned at a fluid dram or one quarter of a tablespoonful. Approximately 5 ml, usually abbreviated tsp.