What is the max/min words for a short story?
Depends. If you're writing it for a magazine, a book compilation or a contest, it's whatever length the editors tell you it is.
Generally speaking, you should be able to read a short story in one sitting. If it's fewer than 1,000 words, it's usually considered a short-short or flash fiction. If it hits 20,000 words, it will probably be called a novella. Anywhere between those two, you get the label short story.
Most often, a short story is between 2,000 to 5,000 words.