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Latin alphabet Aa Bb Cc Dd Ee Ff Gg Hh Ii Jj Kk Ll Mm Nn Oo Pp Qq Rr Ss Tt Uu Vv Ww Xx Yy Zz

The lowercase "i" redirects here. This article is about a letter. For other uses, see I (disambiguation).

Due to MediaWiki's uppercase algorithm, ı, the lowercase dotless i, redirects here.

The letter I is the ninth letter in the Latin alphabet. Its English name is pronounced [aɪ].

Contents 1 History 2 Codes for computing 3 Meanings for I 3.1 Use in Germany 4 See also

History

Egyptian hieroglyph ˁ	Proto-Semitic Y	Phoenician Y	Etruscan I	Greek Iota

In Semitic, the letter Yôdh was probably originally a pictogram for an arm with hand, derived from a similar hieroglyph that had the value of a voiced pharyngeal fricative (/ʕ/) in Egyptian, but was reassigned to /j/ (as in English "yoke") by Semites, because their word for "arm" began with that sound. This letter could also be used for the vowel sound /i/, mainly in foreign words.

The Greeks adopted a form of this Phoenician yodh as their letter iota (Ι, ι). It stood for the vowel /i/, the same as in the Old Italic alphabet. In Latin (as in Modern Greek), it was also used for the consonant sound of /j/. The modern letter J was originally a variation of this letter, and both were interchangeably used for both the vowel and the consonant, only coming to be differentiated in the 16th century.

In modern English, I represents different sounds, mainly a "long" diphthong /aɪ/, that developed from Middle English /iː/ after the Great Vowel Shift of the 15th century, as well as the "short", open /ɪ/ as in "bill". The dot over the lowercase 'i' is sometimes 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.

Codes for 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 astronomy,
  • a lowercase "i" stands for the orbital inclination.
  • the Roman numeral I stands for supergiant in the Yerkes spectral classification scheme.
  • the Roman numeral I (usually) stands for the first-discovered satellite of a planet or minor planet (e.g. Pluto I or (87) Sylvia I Romulus)
• In biochemistry, a capital "I" is the symbol for isoleucine.
• In chemistry, a capital "I" is the symbol for iodine.
• In economics, a capital "I" stands for investment.
• In electronics, a lowercase "i" is a prefix used by Apple Computer for their electronics, such as the iPod and iMac.
• In English, the word I (spelled with a capital "I") is the nominative case of the pronoun denoting the first person singular. See "I" at Wiktionary.
• In the International Phonetic Alphabet, the letter "I" appears in three forms; its lowercase version, /i/, refers to the close front unrounded vowel; its barred version, /ɨ/, stands for the close central unrounded vowel; and its small capital version, /ɪ/, represents the near-close near-front unrounded vowel.
• In Japanese, "I" is a romanization of the kana い and イ.
• In mathematics,
  • A lowercase "i" is used to denote:
    • the imaginary unit, a complex number whose square is equal to −1.
    • an index variable to coordinate vectors or matrices. It is written as a subscript after the indexed element. When used with matrices, it usually indexes rows, in which case columns are usually indexed by j.
  • A capital "I" is used to denote:
    • the closed unit interval, which contains all real numbers from 0 to 1, inclusive
    • the identity matrix.
    • the value of an integral one is trying to evaluate.
• 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)".
  • i is an album by The Magnetic Fields.
  • i is a Portuguese post-rock band
  • I is a song and EP by Swedish tech metal band, Meshuggah.
• In physics and electronic engineering:
  • A capital "I" is used as:
    • a symbol representing the moment of inertia.
    • the variable for electric current. Sometimes both "I" and "i" are used for static and small signal respectively. Therefore the imaginary unit is represented by j instead.
• In QAM modulation schemes, a capital "I" is used to refer to the in-phase communications channel.
• In the world of automobiles:
  • The Mitsubishi i is a car by Mitsubishi motors.
• "I" is the international licence plate code for Italy.
• In programming:
  • the letter i is often used to name an index variable for looping constructs
  • <i> is a deprecated HTML tag for marking italic type.
• In radio, the NATO I band ranges from 8 to 10 GHz.
• In radiocommunication, "I" is the ITU prefix allocated to Italy.
• In Roman numerals, I denotes the number one (there are also separate Unicode characters for this number, 0x2160 "Ⅰ" and 0x2170 "ⅰ").
• In television,
  • the YIQ colorspace (commonly used with the NTSC television encoding scheme) uses a capital "I" to designate the color-difference channel which is in-phase with the subcarrier.
  • i is an American television network formerly known as PAX.

Use in Germany

In Germany, Roman numerals are often used for numbering. When listing things by capital letters of the alphabet, they avoid using the letter I, skipping over to J, to avoid confusion with the alternative Roman numberal numbering system. For example, in every regiment in the German Army there is what would be expressed in English as a "J company" but no "I company."

See also

Ì, Í, Î, Ï, Ĭ, İ, Turkish dotted and dotless I

Two-letter combinations Ia Ib Ic Id Ie If Ig Ih Ii Ij Ik Il Im In Io Ip Iq Ir Is It Iu Iv Iw Ix Iy Iz IA IB IC ID IE IF IG IH II IJ IK IL IM IN IO IP IQ IR IS IT IU IV IW IX IY IZ Letter-digit & Digit-letter combinations I0 I1 I2 I3 I4 I5 I6 I7 I8 I9 0I 1I 2I 3I 4I 5I 6I 7I 8I 9I