- The definition of a twin bed is a small piece of furniture with a mattress designed for a single person to sleep upon.
An example of a twin bed is a dorm bed in college that has room for only one person.
twin bed definition by Webster's New World
Webster's New World College Dictionary Copyright © 2010 by Wiley Publishing, Inc., Cleveland, Ohio. Used by arrangement with John Wiley & Sons, Inc.
either of a pair of single beds
twin bed definition by American Heritage Dictionary
One of a matching pair of single beds.