stabilizing fin
Technical term for a fin or plate used to improve stability, especially in aerodynamics, marine engineering, or similar fields.
ロケットの安定板が飛行中の姿勢を保つ。
The rocket's stabilizing fins keep it stable during flight.
安定翼 is a more general term for a stabilizing wing or fin, while 安定板 often refers to a plate-like fin.
Compound of 安定 (stability) and 板 (plate, board).