Iota Symbol
About Iota Symbol
Ι is the Iota Symbol, the ninth letter of the Greek alphabet in its uppercase form. Ι denotes the imaginary unit in some European notations and underlies the English expression for a vanishingly small amount.
【Pronunciation】 In English, Ι is most often pronounced eye-OH-tuh (IPA: /aɪˈoʊtə/). This is simply the anglicized name of the Greek letter.
The uppercase Iota Symbol Ι is written as a distinct capital Greek glyph and is assigned codepoint U+0399 in the Greek and Coptic Unicode block. In plain or sans-serif fonts it can be mistaken for the Latin letter I, so verify the typeface or context.
【Historical Origin】 Like every Greek letter, Ι was adapted from a Phoenician consonant and entered mathematical and scientific notation through the work of ancient Greek scholars, remaining in continuous use to the present day.
【Common Uses】 Ι is highly active across disciplines and frequently appears alongside other Greek capitals such as Δ (Δ), Σ (Σ), Π (Π) and Ω (Ω) in formulas, papers, and engineering drawings. Its clear shape and long tradition make it a standard symbol in many fields.
How to Type Iota Symbol
Windows Input
Method 1: Hold Alt and type 921 on the numeric keypad, then release Alt to get Ι.
Mac Input
Method 2: Press Control + Command + Space to open the Character Viewer, search for "greek" or "Iota Symbol", then select Ι.
HTML/CSS Input
HTML: Ι or Ι; CSS: content: "\0399";
LaTeX Input
The capital Iota Symbol Ι has no dedicated LaTeX command because it is identical to the Latin capital I; simply type I in math mode to produce Ι.
Iota Symbol FAQ
How is Ι pronounced?
The English pronunciation of Ι is eye-OH-tuh (IPA: /aɪˈoʊtə/). It is the anglicized name of the Greek letter, used directly rather than described as "uppercase Ι".
What is the difference between Ι and the Latin letter I?
Ι (U+0399) is a Greek capital letter, whereas I is a Latin letter; their codepoints and glyphs differ. In a proper typeface Ι and I are clearly distinct, but in plain text or sans-serif fonts they can be confused, so rely on context.
How do I type Ι in Word, web pages, and LaTeX?
On Windows use Alt+921 on the numeric keypad; on Mac open the Character Viewer and search "greek" or "Iota Symbol"; on the web use the HTML entity Ι; in LaTeX simply type the letter I.