I is the 9th letter in the Latin alphabet.

History

The letter I derived from the Greek iota (Ι, ι). It stood for the vowel /i/, the same as in the Old Italic alphabet. In Latin (as in Modern Greek) /j/ (as English Y in YOKE) was added. In Semitic, /j/ was the usual sound value of Jôd (probably originally a pictogram for an arm with hand), /i/ only in foreign words.

In English, I represents different sounds, among them a diphthong that developed from /i:/ as well as short, open /I/ as in BILL. The dot over the lowercase 'i' is called a tittle. In the Turkish alphabet, dotted and dotless I are considered separate letters and both have uppercase (I, İ) and lowercase (ı, i) forms.

Alternate representations

India represents the letter I in the NATO phonetic alphabet.

In international Morse code the letter I is DitDit: · ·

In Braille the letter I is represented as ⠊ (in Unicode), the dot pattern,

.X
X.
..

Computing

In Unicode the capital I is codepoint U+0049 and the lowercase i is U+0069.

The ASCII code for capital I is 73 and for lowercase i is 105; or in binary 01001001 and 01101001, correspondingly.

The EBCDIC code for capital I is 201 and for lowercase i is 137.

The numeric character references in HTML and XML are "I" and "i" for upper and lower case respectively.

Meanings for I

• In biochemistry, I is the symbol for isoleucine.
• In chemistry, I is the symbol for iodine.
• In computing, <i> is the HTML tag for marking italic type. It is also commonly used as the name of the index variable in for loops when no other name suggests itself.
• In English, I is a pronoun denoting the first person, singular.
• In international licence plate codes, I stands for Italy.
• In mathematics,
  • i denotes the imaginary unit, a complex number whose square is -1.
  • I denotes the closed unit interval , which contains all real numbers from 0 to 1, inclusive
  • I denotes the identity matrix.
• In physics and electronic engineering, I is often the variable for electric current. The imaginary unit is represented by j instead.
• In radiocommunication, I is the ITU prefix allocated to Italy.
• In Roman numerals, I denotes the number 1.
• In structural engineering I is used for the moment of inertia
• In music,
  • the roman numeral I is the tonic scale degree, chord, or diatonic function, when distinguished I = major and i = minor.
  • I is the name of the winner of the Norwegian version of Pop Idol and also World Idol, Kurt Nilsen's debut album. See I (album) .
• In economics, I is usually used to represent investment.

See also

Ì, Í, Î, Ï, Ĭ, İ