A five- to seven-story multiple dwelling unit in urban areas, characterized by a long, narrow plan with an indentation on each side, forming a shaft for light and air; hence its resemblance in plan to a dumbbell.
Illustrated Dictionary of Architecture Copyright © 2012, 2002, 1998 by The McGraw-Hill Companies, Inc. All rights reserved
A multiple-dwelling substandard apartment building; commonly three to five stories high, containing relatively long narrow apartments within it; has windows only at the front and rear of each apartment. Shafts located on one or both sides of the apartment provide air and a little light in the rooms that do not face the front or rear of the building. The floor plan of each floor resembles the outline of a dumbbell. Also called a railroad flat.
McGraw-Hill Dictionary of Architecture and Construction. Copyright © 2003 by McGraw-Hill Companies, Inc.