thermonuclear

from The American Heritage® Dictionary of the English Language, 5th Edition.

• adjective Relating to or derived from the fusion of atomic nuclei at high temperatures.
• adjective Relating to or characterized by the use of weapons that employ nuclear fusion, especially as distinguished from those that employ only nuclear fission.

from Wiktionary, Creative Commons Attribution/Share-Alike License.

• adjective Of, or relating to the fusion of atomic nuclei at high temperatures.
• adjective Of, or relating to the use of atomic weapons based on such fusion, especially as distinguished from those based on fission.

from WordNet 3.0 Copyright 2006 by Princeton University. All rights reserved.

• adjective using nuclear weapons based on fusion as distinguished from fission