And to add to the jelly/jam conundrum, we have four or five fruit spreads in the US, all with different names and ingredient lists specified by the government. (Before the Pure Food and Drug Act in the early 1900's, manufacturers could put all sorts of stuff in their jars and call it 'jam',
Chemical additives were used to "heighten color, modify flavor, soften texture, deter spoilage, and even transform … apple scraps, glucose, coal-tar dye, and timothy seed" into a "strawberry jam"
Current regulations specify the fruit/sugar/pectin ratios, so something like strawberry jam doesn't vary much from one brand to another.
Jelly is made from filtered fruit juice, sugar or HFCS, and a pectin to make it 'set'. It's translucent. Grape is the most popular, but you can also get apple, strawberry, apricot, etc.
Jam is made from crushed fruit (sometimes sieved to remove seeds), sugar or HFCS, and pectin. Strawberry is the most popular, but I prefer seedless blackberry and raspberry.
Preserves are about half and half crushed fruit and whole fruit, sugar, and pectin. Especially yummy when you're a little kid and you sneak a whole strawberry out of the jar with a spoon.
Marmalade I think you Brits know about.
There are also fruit spreads that are touted as 'sugar free', but their first ingredient is juice concentrates (pear, grape), which of course is a high-fructose sweetening. It also has a fruit like strawberries or grapes, maltodextrin (dietary fiber), pectin, and citric acid. The manufacturers can't call them jams because of those government regulations so 'fruit spread' is their preferred term.