Keira is a variant of Kira, ultimately derived from Ciara. Ciara originates in Irish language and means "little dark girl". It is a feminine form of Ciar or Ciaran. Currently, Ciara is one of the most popular feminine given names in Ireland. In the United States it is more popular in its variant spelling Kira, Kyra or Keira. Ciara was the name of the 7th century abbess, Saint Ciara of Ireland. In the United States Ciara was popularized by the American musician and actress Ciara Princess Harris, nicknamed simply Ciara. The famous bearer of the name Keira is the British actress Keira Knightley.