stabilizer
Something that keeps things steady and stops wobbling or shaking.
A stabilizer is something that keeps things steady and balanced. When you ride a bike, training wheels act as stabilizers, preventing you from tipping over while you learn. Airplanes have stabilizers on their tails that help them fly straight and level through the air. Ships use stabilizers to reduce rocking in rough seas, making the voyage more comfortable for passengers.
A stabilizer's job is to resist unwanted movement or change. In chemistry, food manufacturers add stabilizers to ice cream to keep it smooth and creamy instead of icy. In photography, a camera stabilizer helps reduce shaky footage when filming while walking.
You'll also hear about economic stabilizers: government programs designed to keep the economy from swinging wildly between boom and bust. The concept is the same whether you're talking about a physical object or an abstract system. A stabilizer counteracts forces that would otherwise cause wobbling, tilting, or unpredictable changes, helping maintain steady, controlled conditions even when external pressures try to throw things off balance.