Where does “teaspoonful” come from?

Teaspoonful comes from English teaspoon, which combines English tea and English spoom, itself from English spume, derived from Latin spuma meaning foam, ultimately from Proto-Indo-European pleh₁-.

teaspoonful (English): A unit of capacity equal to the amount a teaspoon...

Definitions

  1. A unit of capacity equal to the amount a teaspoon...

Ancestry of “teaspoonful”, step by step

teaspoonful traces back through two separate lines of ancestry.

via English teaspoon

StepLanguageWordMeaning
1EnglishteaspoonA small spoon used to stir the contents of a cup...
2EnglishspoonAn implement for eating or serving; a scooped...
3Middle EnglishspoonAlternative form of spone
4Old Englishspōnpiece of wood, chip; sliver, chip of wood,...
5Proto-West Germanicspanupiece of wood, chip, shaving
6Proto-Germanicspenônipple
7Proto-Indo-Europeanpsten-os-
8Proto-Indo-Europeanpstḗnbreast, teat
9Proto-Indo-Europeanph₂ǵ-sth₂-ḗn
10Proto-Indo-Europeansteh₂-to stand

via English ful

StepLanguageWordMeaning
1Englishful
Every word from Proto-Indo-European steh₂-Every word from Proto-Indo-European ph₂ǵ-sth₂-ḗnEvery word from Proto-Indo-European pstḗn