Container that stores values as a single object with a unique name that you define. This name then can be referenced in a rule so that the rule can use the data stored in the object. You can modify the values within the watchlist at any time, and any rule referencing that watchlist will use those new values. For example, if you want to create several rules regarding your stock portfolio, you can create a watchlist containing symbols for all of the stocks that you currently own. When you create your rules, you would reference the watchlist instead of specifying each individual stock symbol in multiple rules. In the future, if your portfolio changes, you would simply modify the watchlist instead of individual rules.