ballast

/ˈbæl.əst/

noun

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

  2. Anything that steadies emotion or the mind.

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

  4. 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.

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

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

verb

  1. To stabilize or load a ship with ballast.

  2. To lay ballast on the bed of a railroad track.