Apolline Delacour was the wife of Monsieur Delacour and the mother of Fleur and Gabrielle Delacour. She was half veela.
Madame Delacour was present for the Third Task of the Triwizard Tournament held at Hogwarts (GF31).
She also attended the wedding of her daughter, Fleur, to Bill Weasley (DH8).
Madame Delacour is described as being a beautiful blonde woman and accomplished at household spells (DH6).
accomplished at household spells (DH6)
Apolline = more than likely derived from the male Apollo who was, among other things, the god of beauty.
Alternatively, she may be named after the Christian martyr known in French as Sainte Apolline (called Saint Apollonia in English), who, before her death, endured all her teeth being pulled or knocked from her mouth. There would be some irony here, since Mrs. Delacour is supposed to be very beautiful and this possible namesake had her looks destroyed. A well-known image showing Sainte Apolline's torture as portrayed in a medieval French mystery play shows the martyr as looking very veela-like (sources: English Wikipedia article, French Wikipedia article).