Nanofiction stories are very very short stories. In the case of tweetzines like Nanoism they have to be 140 characters or less (for reasonably obvious reasons).
See my Selected Nanofiction in our Writing section if you want some more examples.
If you fancy having a go at writing some or you already write them then consider entering Nanoism’s competition.
Everyone can enter one story for free. The clever bit is that if you want to enter more you can if you donate money to a charity of your choice. You can enter one extra story for every dollar you donate.
(Yep, exchange rate issues for some of us but no plan is perfect.) Currency calculator here or consider donating more to be sure. It is Christmas and you choose the charity.
If you need inspiration on charity choice they point you towards Partners in Health. A very good cause.
All the details are available here. Stuff like how to enter, how do they know you’ve donated and the prizes etc.
Good luck. Have fun.