(1):

(n.) Openess; plainess; boldness; positiveness; as, the roundness of an assertion.

(2):

(n.) Fullness; smoothness of flow; as, the roundness of a period; the roundness of a note; roundness of tone.

(3):

(n.) The quality or state of being round in shape; as, the roundness of the globe, of the orb of the sun, of a ball, of a bowl, a column, etc.