ballast

Heavy material that is placed in the hold of a ship (or in the gondola of a balloon), to provide stability.

Anything that steadies emotion or the mind.

Coarse gravel or similar material laid to form a bed for roads or railroads, or in making concrete.

A material, such as aggregate or precast concrete pavers, which employs its mass and the force of gravity to hold single-ply roof membranes in place.

Device used for stabilizing current in an electric circuit (e.g. in a tube lamp supply circuit)

That which gives, or helps to maintain, uprightness, steadiness, and security.

To stabilize or load a ship with ballast.

To lay ballast on the bed of a railroad track.