alpha particle

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noun Physics.

a positively charged particle consisting of two protons and two neutrons, emitted in radioactive decay or nuclear fission; the nucleus of a helium atom.

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Origin of alpha particle

First recorded in 1900–05

Words nearby alpha particle

alpha-linolenic acid, alpha-lipoprotein, alpha male, alpha-naphthylthiourea, alphanumeric, alpha particle, alpha privative, alpha radiation, alpha ray, alpha receptor, alpha rhythm

Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2022

How to use alpha particle in a sentence

Some particles — including protons, neutrons, alpha particles and beta particles — travel through space at high speeds.
Scientists Say: Radiation|Bethany Brookshire|March 29, 2021|Science News For Students
Alpha Team was killed, Faal told the FBI, while the Bravo members who were not gunned down fled.
The Shadowy U.S. Veteran Who Tried to Overthrow a Country|Jacob Siegel|January 6, 2015|DAILY BEAST
The conspirators were split into two teams, “Alpha” and “Bravo.”
The Shadowy U.S. Veteran Who Tried to Overthrow a Country|Jacob Siegel|January 6, 2015|DAILY BEAST
And when that happens, one “alpha dog” will run the show, usually the oldest, most experienced performer, who “knows more tricks.”
A Backstage Love Affair With Cirque du Soleil|Allison McNearney|December 1, 2014|DAILY BEAST

Former RSD instructor Nathan Kole says he saw firsthand how this “alpha male” marketing can damage students.
The Secret World of Pickup Artist Julien Blanc|Brandy Zadrozny|December 1, 2014|DAILY BEAST
Lohse rushes Sigma Alpha Epsilon, gets a bid, endures pledge term, and then submits to the dehumanizing rigors of Hell Night.
An Ivy League Frat Boy’s Shallow Repentance|Stefan Beck|November 24, 2014|DAILY BEAST
This, as a piece of pure economics, does not interest the individual employer a particle.
The Unsolved Riddle of Social Justice|Stephen Leacock
I can tell you, my dear idealist—you have not changed a particle, by the way—that there is another side you have never seen.
Ancestors|Gertrude Atherton
Let us conceive a particle of air situated immediately over the earth's polar axis.
Outlines of the Earth's History|Nathaniel Southgate Shaler
Then let us imagine the particle moving toward the equator with the speed of an ordinary wind.
Outlines of the Earth's History|Nathaniel Southgate Shaler
It was a hair-raising problem, too, and called for every ounce of nerve and every particle of skill the boy possessed.
Motor Matt's "Century" Run|Stanley R. Matthews

British Dictionary definitions for alpha particle

alpha particle

noun

a helium-4 nucleus, containing two neutrons and two protons, emitted during some radioactive transformations

Collins English Dictionary - Complete & Unabridged 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012

Medical definitions for alpha particle

alpha particle

A positively charged nuclear particle, indistinguishable from a helium atom nucleus and consisting of two protons and two neutrons.

Scientific definitions for alpha particle

alpha particle

A positively charged particle that consists of two protons and two neutrons bound together. It is emitted by an atomic nucleus undergoing radioactive decay and is identical to the nucleus of a helium atom. Because of their relatively large mass, alpha particles are the slowest and least penetrating forms of nuclear radiation. They can be stopped by a piece of paper. See more at radioactive decay.