Orchidectomy - excision(removal) of the testicle(s).
See also, orchiectomy because it wasn't good enough that we (humans that speak English) have only one word for something, oh no, we needed two that are almost the same to prove how inventive we are.
May I remind you that these come from my head without references and that you can challenge me if you like? Simply leave a comment and I'll do my best to define your challenge word without help. I'll even let you know if you win. Or course the only prize would be my pride.
And maybe something else.