Thomas Butler Ossory, earl of (ŏs´ərē), 1634–80, Irish nobleman; son of James Butler, 12th earl and 1st duke of Ormonde. Created earl of Ossory in 1662, he was made (1665) lieutenant general in Ireland and often acted as deputy lord lieutenant there for his father. He distinguished himself in naval engagements (1666, 1672) against the Dutch and was made rear admiral in 1673. He carried (1674) to the prince of Orange (later William III) the offer of marriage with Princess Mary and commanded (1677–78) British troops in Flanders.

Thomas Butler: see Ossory, Thomas Butler, earl of.