退化 /tuìhuà/ meaning in English

degeneration [degenerations]▼(condition of a tissue or an organ in which its vitality has become diminished)
noun
[UK: dɪ.ˌdʒe.nə.ˈreɪʃ.n̩] [US: dɪ.ˌdʒe.nə.ˈreɪʃ.n̩]

involution [involutions]▼(shrinking of an organ to a former size)
noun
[UK: ˌɪn.və.ˈluːʃ.n̩] [US: ˌɪn.və.ˈluːʃ.n̩]

retrogression▼(decline)
noun
[UK: ˌre.trə.ˈɡreʃ.n̩] [US: ˌre.trə.ˈɡreʃ.n̩]