Ballast

Part of speech: noun

Pronunciation: /ˈbæl.əst/

Definitions

1. A weighty substance employed in ships or aircraft to ensure stability and balance while also serving to aid in controlling motion during operation and navigation
2. This material is utilized in various vehicles to provide necessary weight for stability, assist in balance, and regulate motion during transit
3. Heavy material placed in ships or aircraft to maintain balance and stability ; crushed stone or gravel laid beneath and around railroad ties to provide a stable base and aid drainage

Etymology: The word "ballast" is built from two plain English parts. "Bar" in its Middle English sense meant "bare," so the first half describes something empty or unladen, and "last" meant "load." Put together, a ballast was the load a ship carried when it had nothing else aboard, weight added to keep the vessel steady and low enough in the water to sail safely. That is the whole of the story, and it explains the modern sense. A ship sailing without cargo rides high and tips easily in the wind, so sailors filled the hold with stones, sand, gravel, or iron until it sat right. Ballast was meant to stabilise, not to earn money, which is why the word came to describe any heavy material used to steady something, from a hot-air balloon to a railway track bed.

Synonyms: weight, counterbalance