vitamin p: a vitamin that maintains the resistance of cell and capillary walls to permeation
entity: that which is perceived or known or inferred to have its own distinct existence (living or nonliving)
quark: (physics) hypothetical truly fundamental particle in mesons and baryons; there are supposed to be six flavors of quarks (and their antiquarks), which come in pairs; each has an electric charge of +2/3 or -1/3