For me, one of the defining features of gravy is that it's made from a roux, but I think that's just because my family always made white gravy as opposed to brown gravy (which is a base thickened with a starch slurry, as opposed to a full on roux).
I have also seen Indian curry bases that are thickened through reduction referred to as gravy, so I think it can/should be a very open term.
This cauliflower recipe is fantastic, thank you for sharing. I love cauliflower steaks but the head are super expensive here so I appreciate anything that turns them into a full meal.
Yeah, same. I tend to think of curry and gravy as two separate things, where gravy is a sauce for something else, but curry is more of the main affair. But some people definitely use gravy as a synonym for the saucy portion of the curry.
As for the recipe, I often bring that one out at thanksgiving or Christmas, and it's always well received. It's usually either that or a stuffed seitan roast. It's definitely one of my go-tos!