'antheridial' originates from New Latin 'antheridium', itself from Greek 'antheridion', where 'anther-' referred to a male reproductive structure (related to 'anther' in botanical usage) and the diminutive suffix '-idion' indicated a small organ.

'antheridion' in Greek became Latinized as 'antheridium' in New Latin; English formed the adjective by adding the suffix '-al' to produce 'antheridial'.

Initially it referred specifically to the small male reproductive organ ('little anther') itself; over time the derived adjective came to mean 'relating to or bearing antheridia' rather than only denoting the organ as a noun.