A panegyris is an Ancient Greek

Ancient Greece

Ancient Greece is a civilization belonging to a period of Greek history that lasted from the Archaic period of the 8th to 6th centuries BC to the end of antiquity. Immediately following this period was the beginning of the Early Middle Ages and the Byzantine era. Included in Ancient Greece is the...

 general, national or religious assembly. Each was dedicated to the worship of a particular god.
It is also associated with saint days and holy festivals.

Relation to Panegyry and Panegyric

Πανήγυρις is also transliterated as panegyry,
and in turn, some sources define panegyry to be a panegyric

Panegyric

A panegyric is a formal public speech, or written verse, delivered in high praise of a person or thing, a generally highly studied and discriminating eulogy, not expected to be critical. It is derived from the Greek πανηγυρικός meaning "a speech fit for a general assembly"...

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A panegyric

Panegyric

A panegyric is a formal public speech, or written verse, delivered in high praise of a person or thing, a generally highly studied and discriminating eulogy, not expected to be critical. It is derived from the Greek πανηγυρικός meaning "a speech fit for a general assembly"...

is a formal public speech. This could be a separate usage of panegyry, an obsolete usage, or simply an error.