seven-hour

The compound adjective "seven-hour" is formed by directly combining the cardinal number "seven" with the noun "hour." The word "seven" has an ancient lineage, tracing back to the Proto-Indo-European root septḿ̥, which is the source for the number seven across many Indo-European languages. "Hour" entered English via Old French and Latin from the Greek hṓrā, which originally meant a period or season before being standardized as a 60-minute division of the day. The compound's logic is transparently descriptive, following the common English pattern of number-noun combinations to specify duration, where the noun remains in its singular form.

Structure: seven (quantity) + hour (unit of time) - seven: From Old English seofon, from Proto-Germanic sebun, from Proto-Indo-European septḿ̥. Functions as a cardinal number. - hour: From Old French hore, from Latin hōra, from Greek hṓrā (season, time). Functions as a noun denoting a unit of time.