fasten down
phr. v..phr. v.. to fix something firmly in place so it cannot move or blow away.
phr. v.. to secure an object to a surface or position using physical restraints such as ropes, bolts, or straps.
You should fasten down the garden furniture before the storm.
The workers had to fasten down the loose roof tiles to prevent any accidents during the high winds.
The crew worked tirelessly to fasten down the heavy equipment on the deck as the ship entered turbulent waters.
often used with physical objects that are outdoors or on moving vehicles.
contrast with 'fasten' (to close a button or belt); 'fasten down' emphasizes securing something to a base or surface to prevent movement.
Fasten down your seatbelt.Fasten your seatbelt.use 'fasten' for closing a belt or buckle; 'fasten down' is for securing an object to a floor or ground.