English Reference

Word

ballast

Phoneticsbal·last, stress on the first syllable

US/ˈbæɫəst/

UK/bˈæləst/

Uncountable noun Nautical

Definition

n. 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.

n. 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.”

Examples

simple

“The ship took on water as ballast to stay stable.”

contextual

“Without enough ballast in the lower hull, the tall ship would be at risk of tipping over in high winds.”

complex

“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

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

Real-World Examples

“These sacs act much like the ballast tanks of a submarine.”
ScienceDaily 27 Jul 2026
“Originally native to the Black and Caspian seas, round goby arrived in the Great Lakes in the early 1990s in cargo ships' ballast.”
Phys.org 18 Aug 2026

Etymology

From Middle English bar (“bare”) + last (“load”).

Etymology adapted from Wiktionary, available under CC BY-SA 4.0.

Domain

Nautical

This entry

Exam level
CambridgeCambridgeCambridge English QualificationsThe exam suite from Cambridge University Press & Assessment, from A1 Movers up to C2 Proficiency. The benchmark names double as CEFR labels.C2 ProficiencyIELTSIELTSInternational English Language Testing SystemThe 0–9 band test co-owned by the British Council, IDP, and Cambridge. Used for university entry, work, and migration.8.5–9.0TOEFL iBTTOEFL iBTTest of English as a Foreign Language, Internet-Based TestETS's academic English test, the standard route for US university admissions. Scored 0–120, with a 1–6 scale since 2026.1–6 scale: 6.0114–120
Frequency
Occasional
Level
C2 · Proficiency
Updated

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English Reference