A dispersion wherein dispersoid particles including colloidal silica and zinc cyanurate are dispersed in a liquid medium. The colloidal silica particles may have an average diameter of 5 to 500 nm, and the dispersion may contain 0.1 to 40% by mass of the particles in terms of SiO2 concentration. Primary particles of the zinc cyanurate may have a major axis length of 50 to 1000 nm, a minor axis length of 10 to 300 nm, and a ratio of major to minor axis length of 2 to 25, and the dispersion may contain 0.1 to 50% by mass of the particles in terms of solids content. A mass ratio of the colloidal silica to the zinc cyanurate particles may be 1:0.01 to 100, and total solids content may be 0.1 to 50% by mass. The liquid medium may be water or an organic solvent.