An electrically neutral particle in the nuclei of all atoms (except hydrogen-1) with a mass slightly larger than that of a proton; in isolation, it has a half-life of about 10.3 minutes. [L. neuter, neither]
- epithermal n. a n. having an energy in the range immediately above the thermal range, i.e., having an energy between a few hundredths and approximately 100 ev.
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neu·tron 'n(y)ü-.trän n an uncharged elementary particle that has a mass nearly equal to that of the proton and is present in all known atomic nuclei except the hydrogen nucleus
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neu·tron (nooґtron) [neutr- + -on] an electrically neutral or uncharged particle of matter existing along with protons in the atoms of all elements except the mass 1 isotope of hydrogen. Symbol n.Medical dictionary. 2011.