an individual 3-dimensional object that has mass and that is distinguishable from other objects

(virology) a complete viral particle; nucleic acid and capsid (and a lipid envelope in some viruses)

a positively charged particle that is the nucleus of the helium atom; emitted from natural or radioactive isotopes

a high-speed electron or positron emitted in the decay of a radioactive isotope

any particle that obeys Bose-Einstein statistics but not the Pauli exclusion principle; all nuclei with an even mass number are bosons

the nucleus of deuterium; consists of one proton and one neutron; used as a bombarding particle in accelerators