stabilizer
/ˈsteɪbəˌlaɪzɚ/
noun
also Brit stabiliser , pl -ers
[count] :a device or substance that is used to make something stable or steady: such as
a device that is used to keep a ship steady in rough seas
the part of an airplane's tail that cannot be moved
a substance that is added to something (such as a food mixture) to keep it in a desired condition
stabilisers [plural] Brit :training wheels