Etymology
O'Clery is an Anglicized form of the Irish surname Ó Cléirigh. The original Irish name means "descendant of the clerk" (from Irish cléireach), a term that referred to a cleric or scholar in medieval Ireland. The prefix Ó denotes a grandson or descendant, indicating a family lineage that traced its roots to a person of religious or scribal profession.
Historical Context
The Ó Cléirigh family were historically a prominent learned sept in medieval Ireland, particularly associated with the north-west region of County Donegal. They were renowned as hereditary historians, poets, and scribes to the O'Donnell lords of Tír Chonaill. The family's scholarly legacy is exemplified by Mícheál Ó Cléirigh (c. 1590–1643), a Franciscan friar and principal author of the Annals of the Four Masters—a monumental compilation of Irish history. The Anglicized forms O'Clery, Cleary, and Clery emerged during the 17th century as part of the gradual shift from Irish to English naming conventions, often enforced under English administration.
Sources: Wikipedia — O'Clery