| the quark having electric charge −1/3 times the elementary charge and bottom quantum number −1. It is more massive than the up, down, strange, and charmed quarks. |
| beauty quark n. See bottom quark. |
| bottom quark n. Abbr. b A quark with a charge of - 1/3 and a mass about 10,000 times that of the electron. Also called beauty quark. See Table at subatomic particle. |
