The word "three-fourths" is a transparent compound formed within Modern English by combining the cardinal number "three" with the pluralized ordinal "fourths." The logic is purely arithmetic: "three" specifies the quantity of parts, while "fourths" specifies the nature of the whole as being divided into four equal segments. This pattern for forming fractions (number + plural ordinal) is a consistent feature of English, seen in terms like "two-thirds" or "seven-eighths." Its meaning is directly derived from the literal sum of its parts, with no significant semantic evolution from its ancient Germanic and Indo-European roots beyond their basic numerical senses.

Structure: three (numeral) + fourths (ordinal fraction) - three: From Old English þrīe, þrēo, from Proto-Germanic þrīz, from Proto-Indo-European tréyes. Functions as the cardinal number. - fourths: From Old English fēorþa (fourth), from fēower (four) + ordinal suffix -þa. The addition of the plural '-s' converts the ordinal into a fractional noun.