four-cylinder

The term is a modern compound adjective formed within English by combining the numeral "four" with the noun "cylinder." "Four" originates from Proto-Germanic fedwōr, tracing back to the Proto-Indo-European root kʷetwóres, a fundamental numeral. "Cylinder" entered English via Old French from the Latin cylindrus, which itself was borrowed from the Greek kylindros, meaning "a roller" or "that which rolls," derived from the verb kylindein, "to roll." The compound "four-cylinder" logically and directly describes the specific mechanical configuration of an internal combustion engine, literally denoting one that possesses four cylindrical combustion chambers or pistons.

Structure: four (number) + cylinder (geometric shape) - four: From Old English fēower, meaning the number after three. A numeral. - cylinder: From Latin cylindrus, from Greek kylindros, meaning a roller or a cylindrical body. A noun used attributively.