Definition of it is (or what) a small world in English:

it is (or what) a small world

phrase

  • Used to express surprise at meeting an acquaintance or discovering a personal connection in a distant place or an unexpected context.

    ‘‘Fancy him being your solicitor. It's a small world.’’
    • ‘Proving that it is a small world, Russ is the son-in-law of Jack.’
    • ‘Meeting you set me to thinking what a small world it was which was topped off by discovering that Rodney's girlfriend's mum walks her dog in the same place that I do, and I know her, and her three legged beastie!’
    • ‘Her last address is in… well, what a small world, Salisbury, Massachusetts.’
    • ‘‘Really,’ he said, ‘I'm from Glendale, Arizona--what a small world.’’
    • ‘This just proves it is a small world after all.’
    • ‘I was chatting with her about my family and studies and it turned out that she had worked with my Mum when she was pregnant with me - it just shows what a small world it is!’