Sindoor

Sindoor is the mark of a married woman in Hinduism. This also lends itself to the name of a wedding ritual in some Hindu communities. The sindoor is first applied to the woman by her husband on the day of her wedding and is called as Sindoor Dana ceremony. After this time she must apply this everyday herself in the parting of her hairline as a sign of marriage.

(source: Sindoor - Wikipedia, the free encyclopedia [link] )