Iota (uppercase
Ι, lowercase
ι) is the ninth letter of the
Greek alphabet. In the system of
Greek numerals it has a value of 10. It was derived from the
Phoenician letter Yodh (.
Iota is pronounced ''yota'' by modern Greeks.
Iota represents (as in
English b''ee''t). In ancient Greek it occurred in both long and short versions, but this distinction has been lost in Modern Greek.
Iota participated as the second element in
falling diphthongs, with both long and short vowels as the first element. Where the first element was long, the iota was lost in pronunciation at an early date, and was written in
polytonic orthography as
iota subscript in other words as a very small ι under the main vowel, for instance
Common English phrase
The word is used in a common English phrase, 'not one iota of difference', to signify a meaningless distinction (lit. "not even a small difference"). The phrase derives from the introduction to the
Antithesis of the Law in the
Gospel of Matthew (''a jot or a
tittle''), and became common in the
theological debate which arose around the time of the
First Council of Nicaea, regarding the nature of the
Holy Trinity. The argument centered on which of two alternative Greek words, differing only in a single 'iota' letter, should be used in describing
Jesus' relationship to the Holy Trinity. One word, '
homoousios', would mean that Jesus was of the ''same'' substance as God the Father, and the other '
homoiousios', would mean that Jesus was of ''similar'' substance.