The "irid-" part means "rainbow," -escent means "bright and shining," so the word carries the idea of being bright and shining like a rainbow. The feathers of a peacock are iridescent, and other brightly color birds, are iridescent. The colors of some butterflies are iridescent. Iridescent colors are bright, shiny, and lustrous. Iridescent colors are brighter than any kind of paint. Soap bubbles sometimes show iridescent colors. I just did a Google Images search on "iridescent" and you should, too. The collection of results is excellent and will show you what the word means better than anything I can say in words.

Iridescent - Shining with many different colors when seen from different angles. This is like when you hold a gemstone, like a diamond, up to the light and you see it break regular light down into a rainbow of color.

It's like luminous. Sort of like when you see a diamond in the light and it reflects different colors. Hope that helps.

Iridescent - Adjective Showing luminous colours that seem to change when seen from different angles.