Classification and use of Stocks vs. Broth:
Broths are the result of cooking meat, not just bones. They're generally the result of preparing another item and usually not prepared specifically on their own. The juices poured off from a roasted turkey (after being degreased) would be considered broth. Whole chickens being poached for another preparation would create broth.
Stocks are made from just the bones. They are prepared specifically for use in other recipes (sauces, soups, stews, rice, etc.) Stocks are never salted in their preparation or the finished dish will most likely end up too salty due to reduction that will take place upon further cooking. Note that homemade stock will be often a bit more broth-like than restaurant/commercial stocks, since it's really hard to get all the meat off the bones.
Stocks are usually simmered for a very long time (4-6 hours for chicken & 8-12 for veal/beef) to extract maximum flavor and gelatin from the bones.
Broths aren't usually cooked nearly as long due to the fact that cooking the meat for extended periods (even chicken surrounded by the liquid) will result in tough, flavorless meat.
Consomme: a fortified and clarified stock. The stock is fortified in flavor by the addition of a "raft" which is a combination of lean ground meat (appropriate to the type of stock being used) with brunoise (1/16 inch) mirepoix (carrots, onions, celery), and egg whites. The raft mixture is stirred into the cold stock and as it gently heats, the proteins coagulate forming a "raft" on top of the stock. A small hole is poked in the center (if one hasn't already formed) and as the stock bubbles through the hole it leaches back through the ground meat/egg white raft which filters out impurities to clarify the stock and fortify it with flavor.
Bouillon: French word for broth.
Court Bouillon: sometimes called a "short broth". A poaching liquid usually used for fish that is usually comprised of water, acid (lemon juice, vinegar, wine), parsley stems, bay leaves, peppercorns, and some salt.
When to use Stock vs. Broth:
Use stock when a sauce is to be reduced significantly or when clarity of the final result is preferred.
Broths can be substituted for stock when the body of the liquid or clarity isn't important, and when the liquid will be thickened by addition of a starch.
Butterscotch and caramel are very different things. The taste difference between the two is far from 'slight' in my opinion.
Caramel is typically made with granulated sugar, milk and/or cream, butter, and sometimes vanilla. The primary flavors of caramel are the sugar and milk/cream.
Butterscotch on the other hand is made with brown sugar. It's primary flavors are brown sugar and butter. It typically also contains milk/cream but they are not as prominent as caramel.
Toffee is butterscotch that has been cooked to the hard-crack stage.
There is no liquor in butterscotch.
There is a lot of leeway in what things get called caramel, butterscotch, and toffee. The important differences to keep in mind are that caramel is made with granulated sugar, whereas toffee and butterscotch are made with brown sugar and much more butter.
Best Answer
Jus generally refers to a sauce or accompaniment, served alongside or on top of some other food.
Stock is a (generally gelatin-rich) broth used during the cooking process, whether as a braising/cooking liquid, or reduced/thickened into another sauce.
There are varying ways to make both; the terminology mainly refers to how they're served or used. In my opinion, "jus" is just a fancified way to refer to a stock served as a final component of a meal rather than an ingredient during cooking.