four-foot-tall

The compound adjective "four-foot-tall" is a modern English construction built from three distinct elements, each with a deep history. "Four" traces back to the Proto-Indo-European root kʷetwóres, which evolved into the Proto-Germanic fedwōr and Old English fēower. "Foot" originates from the PIE root pṓds, meaning 'foot', which became fōt in Old English, later standardized as a unit of length. "Tall" has a more obscure origin, likely from an Old English word meaning 'swift' or 'active', which semantically shifted to describe lofty stature. The logic of the compound is transparently descriptive, combining a numerical quantity, a standard unit of measurement, and an attribute of vertical extent to specify a precise physical dimension.

Structure: four (number) + foot (unit) + tall (height) - four: From Old English fēower, of Proto-Germanic origin; related to Latin quattuor. Functions as a cardinal number. - foot: From Old English fōt, of Germanic origin; related to Dutch voet and German Fuß. Functions as a noun denoting a unit of linear measure. - tall: From Middle English tal, probably from Old English getæl 'swift, prompt'. Its modern sense of 'high in stature' developed in the 16th century. Functions as an adjective describing height.