What is ios?

ios means(iphone operating system)

its a powerful operating system then others.its usiaaly use in every iphone
with a operating system no phones can work or run.ios is operating system for evey apple brand phone or i phones
why its called ios?
Every phones use os(operating System)but i phone use ios.beacause ios full meaning is(iphone operating system)that is why its called ios.its look different from other brand and we know apple means different