The name comes directly from the Spanish word for pilar, its evolution as a name is due to religious associations with the Virgin Mary, usually used in honour of Señora del Pilar (Our Lady of the Piller) according to legend, the Virgin Mary appeared to the apostle St. James the Great, while he was evangelizing in what is now Saragosssa Spain, where she appeared to him floating over a piller. There is a shrine and church dedicated to the occurrence in Saragossa Spain and the name is extremely popular in that particular area of Spain. Popular nickname is Pili. It is sometimes used in conjunction with María or María del. The name is also common in Portuguese speaking countries as well as in the Philippines. In 2002, Pilar was the 94th most popular female name in Spain.
The name is borne by Pilar Ramirez a Mexican synchronized swimmer (b.1964), María del Pilar Pereyra an Argentine butterfly swimmer (b.1978) and Pilar Pallete, Peruvian actress and third wife to the actor John Wayne (b. 1936).
The designated name-day is October 12.