What is (a) A concave molding. (b) A member, whose section is a concave curve, used especially with regard to an inner roof or ceiling, as around a skylight called?

cove — (Arch.) (a) A concave molding. (b) A member, whose section is a concave curve, used especially with regard to an inner roof or ceiling, as around a skylight. (Webster's 1913.)

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