The compound 'three-hundred' is a transparent numerical construction in English, directly combining the cardinal number 'three' with the base unit 'hundred'. 'Three' descends from the Proto-Indo-European root trei-, which is the source for the number three across many Indo-European languages, including Latin trēs and Greek treis. 'Hundred' originates from the Proto-Germanic hundam, related to the concept of a count or a group of ten tens, and is cognate with Latin centum. The compound's logic is purely arithmetic, where 'three' multiplies the quantity represented by 'hundred' to denote the specific cardinal number 300, a formation pattern common to the English numbering system.

Structure: three (numeral) + hundred (numeral) - three: From Old English þrīe, þrēo, from Proto-Germanic þrīz, from Proto-Indo-European tréyes. Functions as the cardinal numeral. - hundred: From Old English hund, hundred, from Proto-Germanic hundą (a count of 100) and hundaradą (literally "count of 120"?), from a base meaning "ten". Functions as the unit of counting.