Chantal is the French form of the Provençal cantal, meaning "stone" or "boulder" — originally a place-name. Saint Jeanne-Françoise de Chantal (1572-1641) founded the Visitation Order with Saint Francis de Sales.
Chantal Akerman (1950-2015) was the Belgian filmmaker (Jeanne Dielman).
Chantal reduces to one — the number of French stone.