The phrase 'multinational country' is correct and usable in written English.
You can use it to refer to any country composed of multiple distinct cultural, ethnic, and linguistic groups. For example, Canada is a multinational country, with both English and French speaking citizens.
"Because of devolution, we now live in a multinational country.
Mr Gurung says the model would be a "multinational country, like Switzerland".
China is a multinational country, with a population composed of a large number of ethnic and linguistic groups.
Racism, as a state policy, is possible only in a very homogeneous country, such as Germany, not in a multinational country like Russia.
Marxist China adopted the linguistic sleight of hand that asserts it has always been a unitary multinational country, not the hub of empires.
In a multinational country, which Yugoslavia is, economic arguments turn only too easily into national ones, with Croats, Serbs or whoever claiming that Macedonians, Slovenes or whatever are getting the privileges they themselves are denied.
But the multinationals' country by country reports will only be available to tax authorities, not publicly.
RE-LY is a phase 3, prospective, randomized, open-label multinational (44 countries) trial of patients with nonvalvular AF and at least 1 risk factor for stroke.
Nine studies were multinational, including countries from Asia, Europe, Latin America, and the Middle-East.
This analysis was based on data obtained from the control arm of the double-blind, randomized, multinational (14 countries), controlled, 4-year PATRICIA trial which enrolled women aged 15 25 years.
Oliveira et al. [ 12] and Gutierrez-Suarez et al. [ 13] reported results from a large multinational (30 countries), cross sectional study of children (3,324 with JIA and 3,315 healthy).
