orchiectomy

n. castration; surgical removal of one or both testes

Castration (also referred as: gelding, neutering, orchiectomy, orchidectomy, and oophorectomy) is any action, surgical, chemical, or otherwise, by which a male loses the functions of the testes or a female loses the functions of the ovaries.
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Orchiectomy /or·chi·ec·to·my/ excision of one or both testes. If bilateral it is called also castration. or·chi·ec·to·my or or·chi·dec·to·my n. [more]Orchiectomy - Community and Resources

Noun
1. surgical removal of one or both testicles
(synonym) orchidectomy
(hypernym) ablation, extirpation, cutting out, excision

The surgical removal of the testicles.