In the Russian constitution the prime minister is actually titled Chairman of the government while the Irish prime minister is called the Taoiseach (which is rendered into English as prime minister), and in Israel he is Rosh HaMemshalah meaning "head of the government". In many cases, though commonly used, "prime minister" is not the official title of the office-holder; the Spanish prime minister is the President of the Government (Presidente del Gobierno).
What is another termfor Rosh HaMemshalah in Russia?