Definition of iOS in English:

iOS

noun

trademark
  • An operating system used for mobile devices manufactured by Apple Inc.

    [as modifier] ‘both the iPod touch and the iPad are iOS devices’
    • ‘For my part, I like Apple's approach to the iOS platform.’
    • ‘They are intended to be read only from the iBooks app on an iOS device.’
    • ‘Expecting developers to design iOS interfaces for three screen sizes seems a bit hard to swallow, too.’
    • ‘Certain software elements, like iOS, were not availabe.’
    • ‘Having a solid understanding of the evolution of Mac OS and iOS will be a challenge.’

Origin

Early 21st century: from i- as in iPod and other products manufactured by Apple Inc. and an abbreviation of operating system.

Pronunciation:

iOS

/ˌīōˈes/