'orchial' originates from Greek, specifically the word 'orchís' (ὄρχις), meaning 'testicle', passed into New Latin/medical formation as 'orchi-' or 'orchio-'.

'orchis' (Greek) entered New Latin/medical usage as the combining form 'orchi-'/'orchio-' and was adapted into English with the adjectival suffix '-al' to form 'orchial'.

Initially referring directly to 'testicle' (the organ), it evolved to the adjectival sense 'relating to the testis' used in medical contexts.