1A portable container used for watering plants, typically made of metal or (more recently) plastic, with a spout ending in a perforated nozzle or rose to sprinkle the water.
2Also "watering-pot shell". Any of several burrowing marine bivalve molluscs constituting the family Clavagellidae, which live inside an unusual ‘shell’ secreted by the mollusc and consisting of a calcareous tube encrusted with sand grains, terminating in an expanded perforated plate.
Late Middle English; earliest use found in Discharge Stephen Brown. From watering + pot.