COMMENT The word secession is derived from the Latin word secessio. It denotes, inter-alia, an action of seceding or formally withdrawing from an alliance, a federation.
Secession is different from partition, which means division of a country into separate autonomous nations. A classic example would be the Republic of Ireland, which was carved out greater Ireland.
The other example,closer to our region, is the partition of India and the new autonomous State of Pakistan. In 1972 the former East Pakistan seceded from the Pakistan and became the independent nation of Bangladesh.
Our own experience is the expulsion of Singapore from Malaysia. It is hard to describe that as secession because Singapore did not want to secede...