pronoun · introductory particle in Classical Chinese used at the beginning of a sentence with no intrinsic meaning

伊谁云从？

abbreviation · demonstrative pronoun meaning 'that', typically used before a noun

自伊时起，他就决定要出国深造。

abbreviation · abbreviation for Iraq (伊拉克 Yī​lā​kè)

两伊战争对中东局势产生了深远影响。

proper name · the Chinese surname Yi

伊先生是我的大学同学。