propellant

1 of 2

adjective

pro·​pel·​lant prə-ˈpe-lənt 

variants or less commonly propellent

: capable of propelling

propellant

2 of 2

noun

variants or less commonly propellent

: something that propels: such as

a

: an explosive for propelling projectiles

b

: fuel plus oxidizer used by a rocket engine

c

: a gas kept under pressure in a bottle or can for expelling the contents when the pressure is released

Examples of propellant in a Sentence

Recent Examples on the Web

Adjective

The heat produced by the reactor is transformed into electricity and this is what ionizes (electrically charges) the propellant gases for use in the ion engine. —Keith Cooper, Space.com, 27 Mar. 2026

After delays due to hydrogen leaks and work back in the Vehicle Assembly Building to fix a propellant pressurization problem, the rocket is being hauled back out to the pad for an April 1 launch try. —William Harwood, CBS News, 19 Mar. 2026

Noun

If all goes smoothly, NASA will start to fill the booster early Wednesday with more than 700,000 gallons of cryogenic propellant. —Tom Costello, NBC news, 30 Mar. 2026

The core stage is the backbone of the rocket and includes engines, propellant tanks and avionics, or aviation electronic systems. —Ashley Strickland, CNN Money, 30 Mar. 2026

Word History

Etymology

Adjective

borrowed from Latin prōpellent-, prōpellens, present participle of prōpellere "to push or thrust forward, compel to go onward" — more at propel

Noun

in part noun derivative of propellant entry 1, in part from propel + -ant entry 1

First Known Use

Adjective

1644, in the meaning defined above

Noun

1654, in the meaning defined above

Rhymes for propellant

• appellant
• libellant
• repellant
• repellent

Kids Definition

propellant

noun

pro·​pel·​lant

variants also propellent

prə-ˈpel-ənt

: something that propels: as

a

: fuel plus a chemical to supply oxygen used by a rocket engine

b

: a gas under pressure in a can for expelling the contents when the pressure is released