What is "teaspoonfuls"

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.

n. (plural of teaspoonful English)