reglet

from The American Heritage® Dictionary of the English Language, 5th Edition.

• noun Architecture A narrow, flat molding.
• noun Printing A flat piece of wood used to separate lines of type.

from The Century Dictionary.

• noun In printing, a thin strip of wood, less than type-high, used in composition to make blanks about a page, or between the lines of large types in open display.
• noun In architecture, a narrow flat molding, employed to separate panels or other members, or to form knots, frets, and other ornaments.

from the GNU version of the Collaborative International Dictionary of English.

• noun (Arch.) A flat, narrow molding, used chiefly to separate the parts or members of compartments or panels from one another, or doubled, turned, and interlaced so as to form knots, frets, or other ornaments. See illust. (12) of column.
• noun (Print.) A strip of wood or metal of the height of a quadrat, used for regulating the space between pages in a chase, and also for spacing out title-pages and other open matter. It is graded to different sizes, and designated by the name of the type that it matches.

from Wiktionary, Creative Commons Attribution/Share-Alike License.

• noun construction A sheet-metal receiver for the attachment of counterflashing. A reglet may be surface-mounted, inset into a raggle or embedded behind cladding.
• noun architecture A flat, narrow moulding, used chiefly to separate the parts or members of compartments or panels from one another, or doubled, turned, and interlaced so as to form knots, frets, or other ornaments.
• noun printing A strip of wood or metal of the height of a quadrat, used for regulating the space between pages in a chase, and also for spacing out title pages and other open matter.