A mangala sutra (from Sanskrit mangala, meaning 'holy, auspicious', and sutra, meaning 'thread') is a necklace that a Hindu or Indian and sub Indian countries' groom ties around the bride's neck in a ceremony called Mangalya Dharanam (Sanskrit for "wearing the auspicious"), which identifies her as a married woman.
This is a social practice widespread in India and Nepal. This practice is also an integral part of a marriage ceremony as prescribed by Manusmriti.
Mangala sutram literally means "an auspicious thread" which is knotted around the bride's neck. It is usually a necklace with black beads strung from a black or yellow thread prepared with turmeric. Sometimes gold, white or red beads are also added to the mangala sutram, depending on regional variation. It is a symbol of marriage worn by women. In certain communities, the groom ties the first knot while his sister tie the rest of the knots.
The significance of the mangala sutra was re-iterated by Adi Shankara in his famous book Soundarya Lahari. According to Hindu tradition, the mangala sutra is worn for the long life of the husband. Dictated by religious customs and social expectations, married women have to wear mangala sutra throughout their life as it is believed that the practice enhances the well-being of her husband.
It is called thaali (താലി) in Malayalam, mangal sutra (मंगळसूत्र) in Marathi, mangalyasutra (ಮಾಂಗಲ್ಯ), thaali (ತಾಳಿ) in Kannada, and thaali (తాళి), maangalyamu (మాంగళ్యము), mangalasutramu (మంగళసూత్రము) or pustelu (పుస్తెలు) in Telugu, thaali (தாலி) in Tamil. Konkanis (Goans and others, both Hindus and Christians) wear three necklaces around their necks, referred to as dhaaremani or muhurtmani (big golden bead), mangalasutra with one or two gold discs and kasithaali with gold and coral beads. In Kerala, a Christian version of the mangalsutra is called a "minnu". In Andhra Pradesh and Telangana regions, the two coin-sized gold discs are separated by 2-3 beads of different kinds. By tradition, one disc comes from the bride's family and another from the groom's side.