specific impulse

American  

noun

Rocketry.

1. a measure, usually in seconds, of the efficiency with which a rocket engine utilizes its propellants, equal to the number of pounds of thrust produced per pound of propellant burned per second.

2. the specific impulse that a given combination of propellants would produce in an ideal rocket engine providing complete combustion, no friction losses, and no lateral expansion of the exhaust.

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specific impulse British  

noun

1. the ratio of the thrust produced by a rocket engine to the rate of fuel consumption: it has units of time and is the length of time that unit weight of propellant would last if used to produce one unit of thrust continuously

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Etymology

Origin of specific impulse

First recorded in 1945–50

Example Sentences

Though some patrons like to go to Lectures on Tap events for specific topics they find interesting, others say they would attend regardless of the subject matter.

From Los Angeles Times • Dec. 9, 2025

The idea was simple: to give people a way to converse and listen in rooms focused on specific topics.

From New York Times • May 24, 2023

Germany’s three governing parties back the idea of appointing consultative bodies made up of members of the public selected through a lottery system who would discuss specific topics and provide nonbinding feedback to legislators.

From Seattle Times • May 10, 2023

There are also hashtags, which let you follow specific topics across servers.

From Slate • Nov. 7, 2022

But his publisher did not think one huge book would sell well and encouraged him to publish smaller books about more specific topics, which is what he did.

From "Charles and Emma: The Darwins' Leap of Faith" by Deborah Heiligman