Topic: A short short story!

The short short story we have to write is 1000 words and the idea of the story comes from generating random ideas for writing short stories link in Mr. Saders' Pingo Lingo blog and there are three of the idea categories that I do not get. They are the Narrative device, the Character as device and Characterization device that I do not get. Can someone explain these to me please. Thank you.