massless


mass·less

M0140100 (măs′lĭs)adj. Having a mass of zero.

massless

(ˈmæslɪs) adj (General Physics) physics having no mass

mass•less

(ˈmæs lɪs)

adj. pertaining to an elementary particle, as a photon, having zero rest mass. [1875–80] mass′less•ness, n.