There is no such function "Linked" (AFAIK). However keyword Linked can be associated with Link tables which is a method to avoid synthetic keys.
For Ex: You have two tables with more than one common fields. Qlikview will create a synthetic key which would be associated with both the tables. In order to avoid those syn keys you can create a composite key in your tables and get rid of those common columns. Now your tables would be connected with the composite key you created and there would not be any syn keys in your data model.
I have two tables TableA and TableB.
Now, when you load these two tables you will get a syn key as they have two common coloumn.
Now, I concatenated Field1 & Field2 to create a key in both tables. My new data model looks like
Apart from this, Linked can also be associated with Linked objects. Once you copy a Qlikview chart or other object to paste it somewhere else in your application. When you do a right click to paste it, you get an additional option to paste object as Link object.
If you select this option the new object would be linked to original object. Now, if you make any change to one object it would be replicated same way in other.
And, if you right click on any object and you see Linked object, that means there are some other objects linked to it and if you change that object other object will also get changed.