(physics) radioisotope (a radioactive isotope of an element)

chemistry (branch of natural science)

an isotope

(Internet slang) Tokutei Asia (East Asian countries which have obvious negative views of Japan)

body

counter for humanoid objects

In general: the body, e.g. of a human or animal / substance; matter / form; shape / (algebra) field (commutative ring with invertible nonzero elements)

outward appearance; look; aspect

transplant rejection / allergic reaction

chain reaction (series of events) / chain reaction (type of nuclear reaction)