how to differ the word 'indian' .. ??

Tweet

we called the person from india as indian but we the word 'indian' is also used to call the natives american how to differ it when people used that word ?? this thing came to my mind last night when i chat with my friend who studied abroad.. and he told me about his indian friend.. i got confused when he said the word indian.. is it indian from india or america ? thanks for responding.. ^^