1. A chief notary or clerk. My private prothonotary.
4. Formerly, one who had the charge of writing the acts of the martyrs, and the circumstances of their death; now, one of twelve persons, constituting a college in the roman Curia, whose office is to register pontifical acts and to make and preserve the official record of beatifications.
(Science: zoology) Prothonotary warbler, a small American warbler (Protonotaria citrea). The general colour is golden yellow, the back is olivaceous, the rump and tail are ash-colour, several outer tail feathers are partly white.