Non-Resident Indian ( NRI )
An Indian citizen or a foreign citizen of Indian origin who stays abroad for employment/carrying on business or vocation or under circumstances indicating an intention    for an uncertain duration of stay abroad is a NON-RESIDENT INDIAN ( NRI ).
(Those who stay abroad on business visit, medical treatment, study or such other purposes which do not indicate an intention to stay there for an indefinite period will not be considered as NRIs. Students who go abroad for studies with an intention to stay there for an  uncertain period and who stayed abroad for more than 180 days in the preceding financial year will be treated as Non Resident Indians).

Foreign Citizen of Indian Origin
For the purposes of availing of the facilities of opening and maintenance of bank accounts,  a foreign citizen (but not a citizen of Pakistan or Bangladesh) is deemed to be of Indian    Origin, if he, at any time was an Indian citizen or either of his parents or any of his    grandparents was a citizen of India. A spouse (not being a citizen of Pakistan or Bangladesh)    of an NRI is also treated as an NRI for the above purposes. For investments in    shares/securities in India, a foreign citizen (but not a citizen of Pakistan, Bangladesh or Sri    Lanka) is deemed to be of Indian Origin, subject to satisfaction of the other conditions above. For investments in immovable properties, a foreign citizen (but not a citizen of Pakistan, Bangladesh, Afghanistan, Bhutan, Nepal or Sri Lanka) is deemed to be of Indian  Origin, if he, at any time, was an Indian citizen or his father or paternal grandfather was an Indian citizen.