What is the name for the 'sweetness' of cooling roast pork? I did a slow roast pork today putting pork knuckles on the bone cooking for 8 hours in a dash of apple juice. 

After cooking, I left it to cool for an hour with the lid on. 

When I lifted the lid, I noticed a 'lightness' to the smell of the pork, almost the lightness you might get when smelling a bouquet of flowers. (Sorry to those who feel this description is overdone - I'm trying to capture an idea in words). 

It almost reminded me of the caramelisation of onion when cooked on a frying pan. 

Help me out here - what is the term I'm looking for? Is it caramelisation?

My question is: What is the name for the 'sweetness' of cooling roast pork?
I don't think there is a word specific to the "sweetness of cooling roast pork" in the English language. This is simply an "aroma", and more specifically, the "aroma of roasted pork". (Or, in my house, "the smell of porky goodness") It is produced by caramelization of the sugars and the Maillard reaction that occurs during roasting.  These are the same mechanisms at work when you caramelize onions, as you point out.