"Quiet Nasal Laughter"

This is appropriate to use when you aren't quite Laughing Out Loud (LOL). QNL is an honest response to the funniest jokes that are exchanged via social media. Instead of making a loud chuckling noise, most of us simply breathe out quickly through our nose to show our mirth. Hence, the term "quiet, nasal laughter." This is the sort of laughter that is appropriate in libraries, in class, or when something is pretty funny.