Madrassa is the Arabic word for school. The concept of the madrassa goes as far back as the mid ninth century AD where they were an early form of private religious education. Historically, madrassas have served a function similar to that of post-secondary education in the West, including studies of Islamic jurisprudence, medicine, and religious studies similar to Western seminaries. Madrassas today are private schools funded by charitable trusts and where public schools exist are not the primary form of education in the Middle East.
In modern times, madrassas are often schools where young children or teenagers are taught Islamic doctrine. Many such school are extremist in character. Such schools exist in the Gaza Strip and the West Bank in Israel, Pakistan, Saudi Arabia, and many other Muslim areas where Islamism is a pervasive ideology. The concept of the madrassa as a terrorist training school is well-founded and there is ample evidence that such madrassas turn out individuals who hold the purpose of attacking the West.