- noun material such as stones carried in the hull of a ship to make it heavier and so less likely to roll
- A layer of coarse stone, gravel, slag, etc., over which concrete is placed.
- The crushed rock or gravel of a railroad bed on which ties are set.
- The transformer-like device that limits the electric current flowing through the gas within a fluorescent lamp.
- A high-intensity discharge that provides a lamp with the proper starting voltage.
- Material placed in a vessel to provide temporary stability.
- For certain types of lamps, one or more devices which serve to provide the proper conditions, such as voltage, for starting and/or operating properly. Fluorescent or mercury lamps may use these.
- noun stones or gravel when used as a foundation for a road or railway track
- noun gravel used in making concrete and in earthworks
Origin & History of “ballast”
Originally, ballast appears to have meant literally ‘bare load’ – that is, a load carried by a ship simply for the sake of its weight, and without any commercial value. English probably acquired it, via Low German, from a Scandinavian language; Old Swedish and Old Danish had not only ballast but also barlast, which appears to betray the word’s component parts: bar, related to English bare, and last ‘burden’ (Old English had hlæst ‘burden’, related to lade, which survived into the 20th century as a measure of weight for various commodities).