| the quark having electric charge − 1/3 times the elementary charge, with strangeness, charm, and other quark quantum numbers equal to 0. |
| down quark n. Abbr. d A quark with a charge of - 1/3 , a mass about 20 times that of the electron, and a downward spin. It is a component of protons and neutrons. See Table at subatomic particle. |
down quark  (doun) Pronunciation Key
A quark with a charge of -1/3. Its mass is greater than that of the electron and the up quark, but smaller than that of all the other quarks. See Table at subatomic particle. |
