I was always taught that $n!$ simple meant multiplying together all numbers up to and including $n$. So for example, $3!$ meant $3 \times 2 \times 1$. Now I discover that $n$ does not have to be an integer. SpeedCrunch, the Linux calculator app will calculate $3.5!$ as $11.6$. So how would I write that down long handed?
To be clear, how would I write down 3.5! as 1 x 2 x 3 x (???). The so called duplicate question does not address this specific issue. Plus I can't understand any of the complex math there; I'm not a mathematician. Can anyone think of a simpler answer?