La Columbārium

1. in architecture, a hole for a horizontal member such as a joist or rafter; a gain or mortise
2. a hole in the side of a waterwheel near its axle, where the water lifted by the wheel exits
3. nautically, an opening for oars in the side of a vessel
4. in burial, an underground chamber for interring cremated remains, with niches for the urns of ashes