having a play of lustrous rainbow-like colors; "an iridescent oil slick"; "nacreous (or pearlescent) clouds looking like mother-of-pearl"; "a milky opalescent (or opaline) luster"
a forceful forward rush or flow; "from the bow she stared at the mesmerising onrush of the sea where it split and foamed"; "the explosion interrupted the wild onrush of her thoughts"