n. A nail with a wide head, traditionally used in the construction and ornamentation of wooden doors.
the GNU version of the Collaborative International Dictionary of English
n. The nail or knob on which in ancient doors the knocker struck; -- hence the old saying, “As dead as a doornail.”
The Century Dictionary and Cyclopedia
n. A large nail or stud fixed in a door to receive the blow of a knocker of simple form.
WordNet 3.0 Copyright 2006 by Princeton University. All rights reserved.
n. a nail with a large head; formerly used to decorate doors
Word Usage
"Snow (UID#1832) on August 24th, 2009 at 5: 05 pm you clearly dont have the IQ of a doornail. a doornail is far smarter than you and it has a purpose."