An abreuvoir (French: watering place, trough), can mean a basin containing water or a type of masonry joint. ==Water basin== An abreuvoir is a watering trough, fountain, or other installed basin: originally intended to provide humans and/or animals a rural or urban watering place with fresh drinking water. They were often located at springs. In pr...
joint or gap between two stones in masonry
• (n.) The joint or interstice between stones, to be filled with mortar.
A`breu`voir' noun [ French, a watering place.] (Masonry) The joint or interstice between stones, to be filled with mortar. Gwilt. 
In architecture, an abreuvoir is a joint or interstice between stones, to be filled with mortar or cement.