Delanny is of American origin, derived from the Irish surname Ó Dealáin, which means 'descendant of Dealán'. It was originally a patronymic surname, indicating that the bearer was a descendant of an ancestor named Dealán. The name Dealán itself comes from the Irish word dealach, meaning 'swarthy' or 'dark-colored'. The given name Delanny is a less common variant of the more familiar Delany, which has been used as both a first and last name since the Middle Ages.
The name Delanny experienced fluctuating popularity over the past two decades, with peaks in 2005 (7 births) and 2014 (9 births), and a recent resurgence in 2021 (7 births). However, it has been relatively uncommon overall, totaling just 61 births between 2003 and 2021.