capful

The word 'capful' is a straightforward Modern English compound. Its first element, 'cap', traces back to Late Latin 'cappa', a term for a hood or a simple covering, which entered English via Old French. The second element, the suffix '-ful', originates from the Old English adjective 'full', meaning 'filled'. Over time, this suffix grammaticalized to form nouns indicating a quantity that fills a specific container. Thus, the literal logic of 'capful' is transparent: it is the quantity required to fill a cap, evolving from the concrete image of a head-covering used as a makeshift measure to a standard unit of volume for small amounts.

Structure: cap (head covering) + ful (full of) - cap: From Latin 'cappa' (a head-covering, hood). In this compound, it functions as the base noun denoting the container. - ful: From Old English '-ful', an adjectival suffix meaning 'full of', which evolved into a noun-forming suffix denoting 'the amount that fills'.