The Collaborative International Dictionary
Teaspoonful \Tea"spoon`ful\ (t[=e]"sp[=oo]n`f[.u]l), n.; pl. Teaspoonfuls (t[=e]"sp[=oo]n`f[.u]lz) or Teaspoonsful. As much as teaspoon will hold; enough to fill a teaspoon. In cooking, it is usually estimated as 4.9 milliliters, which is 1/6 of a fluid ounce, or 1/3 of a tablespoonful. In cooking recipes it may be abbreviated as t.
Note: In the 1890 dictionary, it was defined as a fluid dram or one quarter of a tablespoonful.
Wiktionary
n. (plural of teaspoonful English)
Usage examples of "teaspoonsful".
The nauseous taste may be disguised by administering it covered by Lemon oil, Sassafras oil and other essential oils, or floating on Peppermint or Cinnamon water, or coffee, or shaken up with glycerine, or given in fresh or warmed milk, the dose varying from 1 to 4 teaspoonsful.