Sindoor is a red powder used by married Hindu women. During the marriage ceremony, the groom applies sindoor to the parting of the bride's hair to show that she is now a married woman. Subsequent sindoor is applied by the wife as part of her dressing routine. Once widowed, a woman is not supposed to wear sindoor.

Most women purchase commercial sindoor powder. A traditional component is powdered red lead. Alum and turmeric are sometimes ingredients.

Sindoor must be distinguished from the bindi many Hindu women wear on their forehead, between the eyes. Sometimes the bindi is a symbol of religious affiliation, or a mark of a recent religious ceremony; sometimes the bindi is mere beautification, like the velvet patches or beauty-spots worn by well-dressed European women in the 18th century. Even a widow can wear a bindi.