One who, or that which, interposes or intervenes; an obstacle or interruption; a mediator or agent between parties.
(a) A molding, the convexity of which is one fourth of a circle, being a member just below the abacus in the Tuscan and Roman Doric capital; a torus; an ovolo. (b) One of the shafts of a clustered column. [Written also bowtel, boltel, boultell, etc.]