For a story to be a story, it has to have five basic narrative elements: character, conflict, setting, plot, and theme. (Some folk might argue about that last one.) But a story can be any length.

Here's the shortest one I've ever come across. It was written by Frederic Brown and published in the December 1948 issue of the magazine Thrilling Wonder Stories.

The last man on earth sat alone in a room.

There was a knock on the door.

Looks to me like all the elements are there. What do you think? --GK