12c. shortening of Old English ic, first person singular nominative pronoun, from Proto-Germanic *ekan (cf. Old Frisian ik, Old Norse ek, Norwegian eg, Danish jeg, Old High German ih, German ich, Gothic ik), from PIE *eg-, nominative form of the first person singular pronoun (cf. Sanskrit aham, Hittite uk, Latin ego (source of French Je), Greek ego, Russian ja, Lithuanian aš). Reduced to i by mid-12c. in northern England, it began to be capitalized mid-13c. to mark it as a distinct word and avoid misreading in handwritten manuscripts.
The reason for writing I is ... the orthographic habit in the middle ages of using a 'long i' (that is, j or I) whenever the letter was isolated or formed the last letter of a group; the numeral 'one' was written j or I (and three iij, etc.), just as much as the pronoun. [Otto Jespersen, "Growth and Structure of the English Language," p.233]The form ich or ik, especially before vowels, lingered in northern England until c.1400 and survived in southern dialects until 18c. The dot on the "small" letter -i- began to appear in 11c. Latin manuscripts, to distinguish the letter from the stroke of another letter (such as -m- or -n-). Originally a diacritic, it was reduced to a dot with the introduction of Roman type fonts.
"very small amount," 1630s, figurative use of iota, ninth and smallest letter in the Greek alphabet. Modern use is after Matt. v:18 (see jot), but iota in classical Greek also was proverbially used of anything very small. The letter name is from Semitic (cf. Hebrew yodh).
The symbol for the element iodine.
iThe symbol for current.
iota i·o·ta (ī-ō'tə)
Symbol ι The ninth letter of the Greek alphabet.
The number whose square is equal to -1. Numbers expressed in terms of i are called imaginary or complex numbers.
A shiny, grayish-black element of the halogen group. It is corrosive and poisonous and occurs in very small amounts in nature except for seaweed, in which it is abundant. Iodine compounds are used in medicine, antiseptics, and dyes. Atomic number 53; atomic weight 126.9045; melting point 113.5°C; boiling point 184.35°C; specific gravity (solid, at 20°C) 4.93; valence 1, 3, 5, 7. See Periodic Table.