In physics, thrust is defined as a force opposing to the acceleration of a mass in one direction.
It differs from power which is the quantity of energy provided by an engine per unit of time.
In aviation, thrust is associated with jet engines.
A jet engine accelerates air passing through the system, creating a displacement in the airflow behind it. In reaction to this displacement, thrust is created in the opposite direction, therefore pushing forward the aircraft on which the engine is mounted.