Rating Newest Oldest. Best Answer: `0nii chan` is someone else`s older brother and `nee chan` [onee chan] is older sister. when referring to one`s own older brother `ani chan` is used and older sister is `ane chan`. the word `chan` is used after a given name to adresses children affectionately. It is also used after a kinship word by a small child. the world `san` is also used after a given name. so, `onii chan` and `onii san` is the same person. also, `onee chan ` and `onee san` is same. the word `o` in japanese language is added to a noun,verb or. adjective to indicate respect, humility or ploiteness.