bapti

A ceremony verb, and the ceremony is in the etymology. Bapti is to baptise. The Greek underneath means simply to dip, which is why the churches that immerse rather than sprinkle are the Baptists in English and baptistoj here. The verb is transitive and takes the person as its object: bapti infanon, and the passive esti baptita is how most people describe their own.

The family is entirely regular and unusually useful. Bapto is the act, bapteco the state of being baptised, baptujo or baptopelvo the font. The compounds are where it earns its place: baptopatro is a godfather, baptopatrino a godmother, baptofilo a godson, baptonomo the Christian name or given name, which is the ordinary Esperanto word for a first name in the religious register. Rebapti is to rebaptise.

Who does it. In practice the pastro or, in a Protestant church, the pastoro four ranks earlier in this band. The building is the preĝejo, the institution the eklezio, and the event itself a ceremonio.

One secular use to know. As in English, you can baptise a ship or a nickname: ili baptis la ŝipon Espero, they christened the ship Espero. That is the same verb and the same joke, borrowed by every European language from the same source at roughly the same time.