noun
plural -sions
a combination or mixture of things [count]
[noncount] physics :a process in which the nuclei of atoms are joined
A large amount of energy is released when fusion occurs. - called also nuclear fusion, - compare fission
[noncount] :a type of popular music that combines different styles (such as jazz and rock)
[noncount] :food prepared by combining methods and ingredients from different areas of the world - called also fusion cuisine
US