[Flex time] How many movies have to be in a series before you call it a franchise?

Time to time certain movies are called a franchise, like the James Bond series, Friday the 13th, Fast and the Furious, movies, etc. To be a franchise in your book does it has to have a set number of movies along the original theme even if they are not sequels like 5 movies, half a dozen, too many to count? If a movie only had three of them total, can that be a franchise, or is it the frequency they come out? If every three years or less you can expect another installment of that movie, even if it a stand-alone movie, does that make it a movie franchise?