iota

noun

• 1the ninth letter of the Greek alphabet (Ι, ι), transliterated as ‘i.’.
• (Iota) [followed by Latin genitive] Astronomy the ninth star in a constellation:Iota Piscium

• 2 [in singular, usually with negative] an extremely small amount:nothing she said seemed to make an iota of difference

  [iota being the smallest letter of the Greek alphabet. Compare with jot]