What is the meaning of こと?

broadly, any abstract thing, affair, matter, or fact

  1. a thing, occasion, circumstances, detail, particular

    a thing, occasion, circumstances, detail, particular

    act of (word used for the nominalization of verbs, adjectives, or phrases)

    experience, having been or done

    event of special importance: affair, something, incident, case, occurrence, trouble

    business matters, affairs, business, work, duty

    Used as a nominalizer for precepts.

    It is said that; I've heard that

    Used to introduce aliases/stage names.

    Source: wiktionary.org