Testing of fusion devices. It is called thermonuclear because fusion only happens at very high temperatures. The prefix "thermo" means heat.
You probably mean nuclear fusion
Beacause millions of lives were taken by the nuclear bombs
no
because it has heat inside that can burn you to pieces
The US was the first to start testing nuclear weapons
The Bikini atoll was used for nuclear weapons testing.
By turning it sideways and nudging it with a small thermo-nuclear expolsion
They could be chemical or (thermo)nuclear processes.
In common usage, yes. Its just a short way of saying it.
testing without nuclear explosion
to test nuclear weapons
The most powerful nuclear weapon detonated was the Tsar Bomb which was a 50 megaton thermo-nuclear bomb that was tested in October 30, 1961, in the Novaya Zemlya archipelago