I

In English, I is a pronoun which means "me".

In Azerbaijani, Crimean Tatar, Gagauz and Turkish, the letter I has two kinds, one with a tittle (İ, i) and one without one (I, ı).

Accented forms

In Spanish, Í is used for a stressed I.

In chemistry, I is the symbol for iodine.
In Roman numerals, I means the number one (1).
$i$ is the mathematical symbol for the square root of negative one, also called the imaginary unit.
In physics, I refers to the moment of inertia.

The dictionary definition of i at Wiktionary
Media related to I at Wikimedia Commons

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