Question: is it khmer or cambodian?
Answer: "Cambodia" is the English version of Kampuchea, the official name of the country. "Khmer" (pronounced khmey, at least here in Phnom Penh) is the name the people call themselves by - the country is Kampuchea, the people are Khmer. But no sensible person, Khmer or other, would object if you called them Cambodian.