English Reference
Noun

propellant

n.
C1 Advanced US /pɹəˈpɛɫənt/ UK /pɹəpˈɛlənt/ pro·pel·lant UK spelling propellants

n.a substance that causes something to move or explode. You usually see this word when talking about things like rockets, guns, or fire extinguishers.

n.a substance that provides the force necessary to move an object or cause an explosion. Often refers to the chemical mixture used in firearms or the gas used to propel a rocket.


SIMPLE

The rocket uses liquid hydrogen as a propellant.

CONTEXTUAL

The technician checked the propellant levels in the fire extinguisher before the flight took off.

COMPLEX

Modern aerospace engineering focuses on developing more efficient propellants that provide greater thrust while minimizing the environmental impact of combustion byproducts.

A future supply network could move metals from asteroids to Mars while using propellant produced from asteroid resources.

ScienceDaily· 7 Aug 2026

The only costs would be propellant (perhaps $1.5 million per launch for liquid oxygen, methane, and other consumables) and personnel to manufacture and maintain the rockets and ground support equipment.

Ars Technica· 15 Jul 2026

From propel + -ant.

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

This entry
Level C1 · Advanced
Frequency Occasional
Updated