What differentiates a stew from a casserole?

[Ihopeyourcakeisshit]

Only asking as an acquaintance was most keen to inform me that she has never served her kids stew.
She drops into conversations how she reads The Guardian and listens to radio 4, so I wondered if it was a snobbery thing as I did establish that she will serve a casserole.

My family seem to love a "tagine" whatever the F one of them is

I think it's along the same lines as "cassoulet"

Stew cooked on the job, heat source from below.
Casserole in the oven.
Doesn't matter what's in it, that's what the difference is.

Stew is hob cooked no veg
Casserole oven cooked with chuncky veg

it's all in the consistency.
a casserole has a binding element (noodles, rice, potatoes) and stands firm when cut

This is definitely the difference in the US. A casserole (or hotdish as it is called in the Midwest) and a stew are different things.