General English

  • noun the ninth letter of the alphabet, between H and J
  • noun
    (written as I)
    the Roman numeral for one or first
  • pronoun
    (written as I)
    used by a speaker when talking about himself or herself


  • In the critical path method (CPM) of scheduling, the symbol that represents the event at the start, or initiation, of an activity.


  • A mathematical unit equal to the square root of -1. That is, t2 = -1. It is used in complex numbers. In electronics, the symbol utilized to express the square root of -1 is usually j.
  • (written as I)
    symbol for electric current, or current.
  • chemical symbol foriodine
    (written as I)
  • symbol forinput
    (written as I)


  • symbol forbe
    (written as I)
  • symbol forme
    (written as I)

Cars & Driving

  • symbol forinjection

Origin & History of “i”

Essentially all the Indo-European languages share the same first person singular pronoun, although naturally it has diverged in form over the millennia. French has je, e.g., Italian io, Russian ja, and Greek egṓ. The prehistoric Germanic pronoun was *eka, and this has produced German ich, Dutch ik, Swedish jag, Danish jeg, and English I. The affirmative answer aye ‘yes’ (16th c.) is probably ultimately the same word as I.