Iota

Iota (/aɪˈoʊtə/ ⓘ; /ˈjota/, uppercase Ι, lowercase ι; Greek: ιώτα) is the ninth letter of the Greek alphabet. It was derived from the Phoenician letter Yodh. Letters that arose from this letter include the Latin I and J, the Cyrillic І (І, і), Yi (Ї, ї), and Je (Ј, ј), and iotated letters (e.g. Yu (Ю, ю)). In the system of Greek numerals, iota has a value of 10.

Iota represents the close front unrounded vowel IPA: [i]. In early forms of ancient Greek, it occurred in both long [iː] and short [i] versions, but this distinction was lost in Koine 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. Examples include ᾼ ᾳ ῌ ῃ ῼ ῳ. The former diphthongs became digraphs for simple vowels in Koine Greek.

The word is used in a common English phrase, "not one iota", meaning "not the slightest amount". This refers to iota, the smallest letter, or possibly yodh, י, the smallest letter in the Hebrew alphabet. The English word jot derives from iota. The German, Polish, Portuguese, and Spanish name for the letter J (Jot / jota) is derived from iota.

Uses

In some programming languages (e.g., A+, APL, C++, Go), iota (either as the lowercase symbol ⍳ or the identifier iota) is used to represent and generate an array of consecutive integers. For example, in APL ⍳4 gives 1 2 3 4.
The lowercase iota symbol is sometimes used to write the imaginary unit, but more often Roman i or j is used.
In mathematics, the inclusion map of one space into another is sometimes denoted by the lowercase iota.
In logic, the lowercase iota denotes the definite descriptor.
Turned iota ⟨℩⟩ was formerly used for the Sinological phonetic notation letter now transcribed as ⟨ɿ⟩.

Unicode

For accented Greek characters, see Greek diacritics: Computer encoding.

U+0196Ɩ LATIN CAPITAL LETTER IOTA
U+0269ɩ LATIN SMALL LETTER IOTA
U+0345ͅ COMBINING GREEK YPOGEGRAMMENI
U+037Aͺ GREEK YPOGEGRAMMENI
U+038AΊ GREEK CAPITAL LETTER IOTA WITH TONOS
U+0390ΐ GREEK SMALL LETTER IOTA WITH DIALYTIKA AND TONOS
U+0399Ι GREEK CAPITAL LETTER IOTA (Ι)
U+03AAΪ GREEK CAPITAL LETTER IOTA WITH DIALYTIKA
U+03AFί GREEK SMALL LETTER IOTA WITH TONOS
U+03B9ι GREEK SMALL LETTER IOTA (ι) (\iota in TeX)
U+03CAϊ GREEK SMALL LETTER IOTA WITH DIALYTIKA
U+1D7Cᵼ LATIN SMALL LETTER IOTA WITH STROKE
U+1DA5ᶥ MODIFIER LETTER SMALL IOTA
U+1FBEι GREEK PROSGEGRAMMENI
U+2129℩ TURNED GREEK SMALL LETTER IOTA (&iiota;)
U+2373⍳ APL FUNCTIONAL SYMBOL IOTA
U+2378⍸ APL FUNCTIONAL SYMBOL IOTA UNDERBAR
U+2C92Ⲓ COPTIC CAPITAL LETTER IAUDA
U+2C93ⲓ COPTIC SMALL LETTER IAUDA
U+A646Ꙇ CYRILLIC CAPITAL LETTER IOTA
U+A647ꙇ CYRILLIC SMALL LETTER IOTA
U+1D6B0𝚰 MATHEMATICAL BOLD CAPITAL IOTA
U+1D6CA𝛊 MATHEMATICAL BOLD SMALL IOTA
U+1D6EA𝛪 MATHEMATICAL ITALIC CAPITAL IOTA
U+1D704𝜄 MATHEMATICAL ITALIC SMALL IOTA
U+1D724𝜤 MATHEMATICAL BOLD ITALIC CAPITAL IOTA
U+1D73E𝜾 MATHEMATICAL BOLD ITALIC SMALL IOTA
U+1D75E𝝞 MATHEMATICAL SANS-SERIF BOLD CAPITAL IOTA
U+1D778𝝸 MATHEMATICAL SANS-SERIF BOLD SMALL IOTA
U+1D798𝞘 MATHEMATICAL SANS-SERIF BOLD ITALIC CAPITAL IOTA
U+1D7B2𝞲 MATHEMATICAL SANS-SERIF BOLD ITALIC SMALL IOTA

Iota

Uses

Unicode

See also