Operator
A value containing a reference to an Operator. Operators can be partially applied for more flexible evaluations based on the concept of Currying. This is part of the concept of metaprogramming (look it up, it's a thing!), where operators are treated as data by other operators. This basically allows you to create new operators yourself, which can then be used for more complex operations.
You can for example store the addition Operator in a variable card. Do this by starting to type the operator name and selecting it from the autocomplete dropdown-list and clicking it. You can then partially apply it with one Integer Variable Card, which will result in a new virtual operator with one input type and one output type, which internally contains a reference to that applied Integer. Applying another Integer will result in an Integer.
Other operations of Operators are present in the Logic Programmer for more advanced evaluations, such as reducing a list to a single value, or filtering a list based on a Predicate.