iota

/aɪˈoʊtə/
noun
  1. A very small amount; a tiny bit.
    • She didn't care one iota about what others thought.
    • There is not an iota of truth in that rumor.
    • He changed his plans by an iota after hearing the news.
  2. The ninth letter of the Greek alphabet (Ι, ι).
    • The Greek letter iota looks similar to the English letter 'i'.
    • The symbol for iota is often used in mathematics and science.
    • In ancient Greek, iota could represent a short vowel sound.