Overview
Saptapadi (Sanskrit: सप्तपदी, Saptapadī, literally 'taking together seven steps'), also known as saat phere (Marathi: सात फेरे, literally 'seven circumambulations'), is regarded as the most important rite (Sanskrit: rītī) of a Hindu wedding ceremony. The term denotes the act of the bride and the groom walking seven steps together, or completing seven rounds around a sacred fire.
In this rite, the bride and the groom tie a knot and proceed together, accompanied by one vow at each step. The sacred fire (agni) is considered the witness to the union, in keeping with the wider Hindu ritual tradition in which fire serves as a divine attestor of solemn undertakings.
Each of the seven steps is associated with a specific vow exchanged between the couple. The marriage is considered complete only after the seventh step has been taken, marking Saptapadi as the decisive ritual moment of the wedding ceremony within Hindu tradition.
References
Adapted from the English Wikipedia article on Saptapadi.