Iota represents the close front unrounded vowelIPA:[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.[4] 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.[4]
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.[citation needed] The English word jot derives from iota.[5] The German, Polish, Portuguese, and Spanish name for the letter J (Jot / jota) is derived from iota.
Symbol
In some programming languages (e.g., A+, APL, C++,[6]Go[7]), 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.
U+0390ΐGREEK SMALL LETTER IOTA WITH DIALYTIKA AND TONOS
U+0399ΙGREEK CAPITAL LETTER IOTA (Ι)
U+03AAΪGREEK CAPITAL LETTER IOTA WITH DIALYTIKA
U+03AFίGREEK SMALL LETTER IOTA WITH TONOS
U+03B9ιGREEK SMALL LETTER IOTA (ι) (\iota in TeX)
U+03CAϊGREEK SMALL LETTER IOTA WITH DIALYTIKA
U+1D7CᵼLATIN SMALL LETTER IOTA WITH STROKE
U+1DA5ᶥMODIFIER LETTER SMALL IOTA
U+1FBEιGREEK PROSGEGRAMMENI
U+2129℩TURNED GREEK SMALL LETTER IOTA (℩)
U+2373⍳APL FUNCTIONAL SYMBOL IOTA
U+2378⍸APL FUNCTIONAL SYMBOL IOTA UNDERBAR
U+2C92ⲒCOPTIC CAPITAL LETTER IAUDA
U+2C93ⲓCOPTIC SMALL LETTER IAUDA
U+A646ꙆCYRILLIC CAPITAL LETTER IOTA
U+A647ꙇCYRILLIC SMALL LETTER IOTA
These characters are used only as mathematical symbols. Stylized Greek text should be encoded using the normal Greek letters, with markup and formatting to indicate text style:
U+1D6B0𝚰MATHEMATICAL BOLD CAPITAL IOTA
U+1D6CA𝛊MATHEMATICAL BOLD SMALL IOTA
U+1D6EA𝛪MATHEMATICAL ITALIC CAPITAL IOTA
U+1D704𝜄MATHEMATICAL ITALIC SMALL IOTA
U+1D724𝜤MATHEMATICAL BOLD ITALIC CAPITAL IOTA
U+1D73E𝜾MATHEMATICAL BOLD ITALIC SMALL IOTA
U+1D75E𝝞MATHEMATICAL SANS-SERIF BOLD CAPITAL IOTA
U+1D778𝝸MATHEMATICAL SANS-SERIF BOLD SMALL IOTA
U+1D798𝞘MATHEMATICAL SANS-SERIF BOLD ITALIC CAPITAL IOTA
U+1D7B2𝞲MATHEMATICAL SANS-SERIF BOLD ITALIC SMALL IOTA
