A mech (or mecha) is a name for a robot-like creature that is usually controlled by a pilot, whether human or some other species.
Often depicted as a vehicle (and weapon of destruction) used for war, a mech has also been shown as an aid in construction,
transportation, handling of hazardous
materials, etc - essentially giving its human pilot "extra human" strength and protection.
In The Last Machinist, mechs that were built to aid humans were known as Strongfairs. When the threat of war loomed, the Strongfairs were confiscated and dismantled for parts, used to construct Kir Nero's Ryders of Destruction.