BAL'LAST, noun 1. Heavy matter, as stone, sand or iron, laid on the bottom of a ship or other vessel, to sink it in the water, to such a depth, as to enable it to carry sufficient sail, without oversetting. Shingle ballast is ballast of coarse gravel. 2. Figuratively, that which is used to make a thing steady. BAL'LAST, verb transitive To place heavy substances on the bottom of a ship or vessel, to keep it from oversetting. 2. To keep any thing steady, by counterbalancing its force.
Source: Webster's 1828 American Dictionary ↗ · public-domain · returned verbatim, no AI