Definition of rest mass in English:

rest mass

Syllabification: rest mass


  • The mass of a body when at rest.
    More example sentences
    • The concept of the rest mass derives from special relativity.
    • The neutrino was known from the start to be an extraordinarily light particle, perhaps massless, since its rest mass could never be detected.
    • Any object with a non-zero rest mass (like a dust mote) can never reach light speed.

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Word of the day skosh
Pronunciation: skōSH
a small amount; a little