Definition of zillionth in English:

zillionth

Pronunciation /ˈzilyənTH/ /ˈzɪljənθ/

ordinal number

informal
  • 1Used to emphasize that something has happened repeatedly many times.

    • ‘for the zillionth time, it's not a big deal’
    • ‘I had my zillionth trip to the hospital’
  • 2A tiny fraction of something.

    • ‘a few zillionths of a percentage’