In defence of "PB & J's"

Ok, peanut butter can be almost sweet to not at all depending on the brand's added sugar (horrors, I know).

In the USA, a jam has fruit, sugar and a very small amount of fixer-pectin, usually. Really 'fancy' jams are called preserves.  

A jelly in the USA  has less actual fruit, more sugar and more pectin. Cheaper and more consistent than a jam or preserve. It does get confusing as most makers produce both styles in all the fruit flavors offered.

  I know jelly in the UK is more likely what we'd call gelatin here.  No way am I spreading that on my toast.

A sandwich made with either loses flavor and consistency very quickly, but rarely spoils after a few hours of heat.

The ultimate kid version, adds the spun marshmallow product, usually with 'fluff' in the product name.

  Think Stay-puff, but easily spreadable. 

Personal favorite version is made with toasted rye bread,  using blackberry jam. Goes good with hot black coffee.

The taste of most peanut butter brands is preferable that stuff called vegamite, at least to all the 'Yanks' in my acquaintance.

My opinions are my own. The differences in jelly, jam and preserves are not legal product terms, but everyone would know if a product was misrepresented.