four-thirty

The compound "four-thirty" is a modern English construction formed by combining two cardinal numbers to denote a specific time. The first element, "four," traces back to the Proto-Indo-European root kʷetwóres, which evolved into the Proto-Germanic fedwōr and eventually Old English fēower. The second element, "thirty," originates from the Proto-Germanic þrīz tigiwiz, meaning "three tens," composed of the root for "three" and a suffix denoting a decade. This transparent numerical compounding follows the standard English convention for telling time, where the hour precedes the minutes. The logic is purely arithmetic, directly reflecting the time as four hours plus thirty minutes, with the morphemes retaining their core numerical meanings.

Structure: four (number) + thirty (number) - four: From Old English fēower, of Proto-Germanic origin; related to Dutch vier and German vier, from an Indo-European root shared by Latin quattuor and Greek tessares. Functions as the cardinal number in the compound. - thirty: From Old English þrītig, from þrīe (three) + -tig (group of ten); of Germanic origin. Functions as the cardinal number representing three tens in the compound.