pulsar

noun

pul·​sar ˈpəl-ˌsär 

: a celestial source of pulsating electromagnetic radiation (such as radio waves) characterized by a short relatively constant interval (such as .033 second) between pulses that is held to be a rotating neutron star

Examples of pulsar in a Sentence

Recent Examples on the Web

As the pulsar spins, these beams sweep across the cosmos like the beams of light from a lighthouse. —Robert Lea, Space.com, 21 Feb. 2026

The two planets, roughly four times the size of Earth, were discovered to be orbiting around a millisecond pulsar star named PSR B1257+12, which is 2,300 light-years away. —Lorenzino Estrada, AZCentral.com, 9 Jan. 2026

In 1992 that changed, when astronomers spotted two planets orbiting a pulsar 2,300 light years from Earth. —Jeffrey Kluger, Time, 2 Jan. 2026

What is a neutron star, or pulsar? —Adam Harrington, CBS News, 23 Dec. 2025

Word History

Etymology

puls(ating) + -ar (in quasar)

Note: The coinage was apparently made by the astronomers Jocelyn Bell Burnell (born 1943 in Northern Ireland) and Antony Hewish (born 1924 in England), who discovered the objects in November, 1967. The Oxford English Dictionary, 3rd edition, cites the following from the Daily Telegraph (March 5, 1968, p. 21): "The name Pulsar (Pulsating Star) is likely to be given to it … Dr. A. Hewish … told me yesterday: '…I am sure that today every radio telescope is looking at the Pulsars.'" The word pulsar was not used in the first formal report of the discovery (A. Hewish, S.J. Bell, et al., "Observation of a Rapidly Pulsating Radio Source," Nature, vol. 217, February 24, 1968, pp. 709-13).

First Known Use

1968, in the meaning defined above