What is Resort Casual, Resort Formal or Mountain Casual?

I've had a few invitations recently where the agenda said, "resort wear" or "mountain casual". What does that really mean? I work at home (I don't get out much) so when I received an invite to an event that said one night would be "resort casual" and the other will be "resort formal" I was in a bit of a quandry as to what that means.

I have two ways to get fashion information. I either call my sister (who has always been a fashionista - even since the days of working at County Seat so she could get a discount) and I also turn to Pinterest. I figured out that Resort Casual is a bit more dressed up than slumming on the beach (good thing - this was a work event after all). So I chose a sun dress with giant flowers. All of the pinterest pictures showed flowers.

When it came to Resort Formal. I went shopping with my sister. We ended up at Black & White Market - where she chose a black jersey fabric strappy pant-suit with sparkles along the top (and a snazzy tie at the waist). She also said that I absolutely HAD to have the necklace and earrings. She promptly asked if she could borrow them the week following. It seemed perfect. I fit in.

Not just two weeks later, I received an invite that says "mountain casual". Seeing as though I've lived in Colorado all my life - I think I pretty much know what mountain casual is. Mountain Casual usually includes jeans - so I'm much more comfortable there....but then what? What to wear with jeans? I chose a medium weight sweater (we were going to Vail/Beaver Creek in October - the weather can make giant swings). A long sleeve shirt and a scarf. Done.

What would you wear for Resort Casual, Resort Formal or Mountain Casual? Next up? Cancun. What is beach wear? I got this one! Flip flops, bathing suits and cover-ups! Done!