Kiera is an anglicized feminine form of the Irish Ciarán and Ciara, from ciar, "dark" or "black-haired". The spelling Keira became familiar through actress Keira Knightley, while Kiera follows the Irish pronunciation more closely. In the United States Kiera ranked number 444 in 2000, peaked at number 293 in 2007 and has eased out of the top 1000 since 2022, standing at number 1097 in 2025.