1) Moulding on a wall 
[urban planning] Coving is a method of urban planning used in subdivision and redevelopment of cities characterized by non-uniform lot shapes and home placement. When combined with winding roads, lot area is increased and road area reduced. Coving is used as an alternative to conventional `grid` land development layout in order to enhance c...
• (p. pr. & vb. n.) of Cove • (n.) A cove or series of coves, as the concaved surface under the overhang of a projecting upper story. • (n.) The splayed jambs of a flaring fireplace.
in architecture, concave molding or arched section of wall surface. An example is the curved soffit connecting the top of an exterior wall to a ...
Decorative moulding adjoining the top of an interior wall and the ceiling..
A shaped moulding joining a wall to the ceiling.
Cov'ing noun (Architecture) (a) A cove or series of coves, as the concaved surface under the overhang of a projecting upper story. (b) The splayed jambs of a flaring fireplace. 
In architecture, coving is the series of coves fitted as the concaved surface under the overhang of a projecting upper story. The term is also applied to the splayed jambs of a flaring fireplace.
A curved moulding at the junction between a walls and ceiling of a room
The concave decorative moulding that joins a ceiling to the walls.