fissão

(feminine) fission (process whereby one item splits to become two)
(abbreviation, alt-of, ellipsis, feminine) ellipsis of fissão nuclear (“fission”)
(feminine) fission (process by which a bacterium splits into two)

kernsplitsing

Learned borrowing from Latin fissiōnem.

Practice speaking and memorizing "fissão" and many other words and sentences in Portuguese.