Upset stomach?

[Frazzled13]

Bit of a silly question I’m sure but, what do you mean when you say “upset stomach.”
I only ask because I’ve got some medication which lists as potential side effects “abdominal pain, nausea, vomiting, diarrhoea, upset stomach”
Do the first four not cover what an upset stomach is? Why list it separately? (Yes, I know I’m overthinking a medication leaflet and it doesn’t actually matter)
When people say it, is it just a delicate way of saying d&v?

For me, an upset stomach is runs, stomach ache, queasiness, not fancying food. I wouldn't classify vomiting as an upset stomach

The shits. Runny bum. Pissing out of your arse.

I would class an upset stomach as a little nausea, mild to moderate cramps and a few bouts of diarrhoea.