https://en.m.wikipedia.org/wiki/Thermonuclear_weapon https://en.m.wikipedia.org/wiki/Thermonuclear_weapon The "hydrogen" in "hydrogen bomb" relates to fusion.

https://en.m.wikipedia.org/wiki/Thermonuclear_weapon https://en.m.wikipedia.org/wiki/Thermonuclear_weapon The "hydrogen" in "hydrogen bomb" relates to fusion. In a nutshell, these types of devices use a fission bomb to create the environment (pressure/temperature) that causes lighter atoms to undergo fusion, which significantly boosts the explosive yield compared to a pure fission bomb.