O'Leary
An Irish surname meaning “descendant of Laoghaire,” an old Gaelic personal name associated with a keeper of cattle or a plowman, depending on the interpretation.
The #2,351 most common surname in the United States (2010 Census) — about 1 in every 19,913 Americans shares it.
Etymology
Leary is an Anglicized form of Irish O'Leary, from Gaelic Ó Laoghaire, meaning “descendant of Laoghaire.” The personal name Laoghaire is ancient and has been variously explained by 19th-century scholars; one common explanation connects it with laighre/laidir-type roots suggesting strength, while older sources also offered other readings. In practice, the surname is best understood as a family name from a Gaelic ancestor’s given name rather than a word describing a trade or place.
History
The name is strongly associated with Ireland and is especially well known through the Munster O'Learys. In English records, the prefix O' was often dropped, producing forms like Leary, O'Leary, and occasionally shortened or altered variants in migration and registration. 19th-century surname dictionaries consistently treat it as an Irish Gaelic family name, though they differ on the exact meaning of Laoghaire.
Origin
Regions
Variant spellings
Fun fact
The name survives both with and without the O' prefix, so modern Leary families may be directly linked to the older Irish O'Leary line.
From the historical record
“LEARNED, LARNED. Same as Learnard. LEARY. Corrupted from the Ir. name Laeghaire ; from laidir, strong, stout, or laghar, prong, fork, toe. LEATHER. Same as Lethar, name of a bishop at the time of Ethelbert. Forstemann refers the 0. G. names Leither, Lethar, LUDUS PATRONYMICUS. 55 Mod. G. Leder, to 0. H. G. leid, 0.…”
— Ludus Patronymicus; or, the etymology of curious surnames