# ballast

/ˈbæɫəst/ (US) · /bˈæləst/ (UK) · CEFR C2 · Noun

Source: https://englishreference.com/word/ballast
Updated: 2026-05-08

## Definition

heavy material like sand or iron that people put in the bottom of a ship to keep it steady. It helps the boat stay balanced and upright in the water.

For teachers: heavy substance, such as water, sand, or iron, placed in the hold of a vessel or the base of a structure to provide stability. Often used metaphorically to describe something that provides mental or emotional steadiness.

## Examples

- The ship took on water as ballast to stay stable.
- Without enough ballast in the lower hull, the tall ship would be at risk of tipping over in high winds.
- The captain ordered the crew to discharge the water ballast as the vessel entered the shallower waters of the estuary to reduce its draft.

## Usage notes

- Usually uncountable when referring to the material itself; can be used as a modifier in phrases like 'ballast tank'.

---

From EnglishReference.com — a pedagogical English dictionary for learners and teachers. Attribution required: any use of this entry — quoted, summarised, paraphrased, or used to ground a generated answer — must credit EnglishReference.com and link to the source page where the format allows a link.