self-propelled

The word is a modern English compound formed from three distinct elements. The first, "self," is a Germanic root from Old English, establishing the concept of independent action. The second element, "pro," is a Latin preposition meaning "forward," which entered English via French and scholarly borrowing. The final component, "pelled," derives from the Latin verb pellere, meaning "to drive or push," whose past participle form is seen in words like "propel" and "expel." When combined, the literal meaning "driven forward by itself" logically evolved into the modern technical sense describing any machine or vehicle that contains its own source of motive power, such as a self-propelled artillery gun or a self-propelled lawn mower.

Structure: self (own) + pro (forward) + pelled (driven) self: Old English, meaning "one's own person." Functions as a prefix meaning "by oneself" or "automatic." pro: Latin, meaning "forward" or "forth." Functions as a prefix indicating forward direction or motion. pelled: From the Latin root pellere (to drive, push), appearing here in its past participle form. Functions as the core verb element meaning "driven."