The lustral basin is an architectural form used in Minoan architecture. Consisting of a small sunken room reached by a staircase, they are characteristic of elite architecture of the Neopalatial period (c. 1750-1470 BC).
They are hypothesized to have been used either as shrines, baths, or as part of an initiation ritual. The term was coined by Sir Arthur Evans, who hypothesized that they were used for lustration.