'Casual'

What exactly does that mean?

I know what 'casual' sex means
That's a no-brainer...

If I'm going to a birthday party
At a bar or restaurant
And they say 'casual'
That's easy
Jeans, t-shirt, etc.

If it's 'casual' Friday at work
That's easy
Jeans, shirts. etc
(Although I do notice people go a little
overboard and take 'casual' Friday to a place
it shouldn't...no trackpants in the workplace, please)

But, when a wedding invitation states
"Casual" and wear 'comfortable shoes'
What does that mean?
My first thought when I read
"Casual" with "comfortable shoes"
Is
"Great, I'm heading to Lilith Fair!"
(Which rocked, by the way...
Sarah has to start that up again)

No.
I'm heading to that 'wedding'
I was telling you guys about a few weeks ago
Up on the lake
In the bush
Because the ceremony is taking place
Beside a particular tree
And it's pot luck, remember?

Anyway, what the F*** is one supposed
To wear to a 'Casual' 'wedding'??

I don't do sundresses, I'm afraid.
In case that was going to be your suggestion...

Oh yeah..it's going to be sunny and warm, too.

I think I have decided on my
Light beige Khaki's
Kinda capri
But not REALLY
Low waisted a bit
But not butt-crack low

I'm torn on the top though.

Any suggestions?