When you let air out of your nose when something isn't funny enough to actually laugh at.
That joke was so lame but I did a nose laugh.
by Alexandra2847 August 30, 2006
a laughing technique where all the sound of the person's laughter comes through the nose. A very subdued demonstration of mirth.
The best example is the song in the movie "Mary Poppins", where Bert is describing ways that people laugh. He mentions and demonstrates people who laugh through their noses.
by Anne Ringer March 24, 2005