A dead key state is an internal state within the operating system, part of the way that keyboard input is processed. When the user types a dead key, the system enters the corresponding dead key state, which is how the system decides what output to produce for the next key.

Another way of thinking of it is that the system takes note of the dead key, and it will look up the next key in a special table. If there is an entry for the next key in that table, the corresponding output is produced.

Dead key states have names. You don’t have to know the name, or assign one yourself. However, it is useful in some cases to know the name of the dead key state. If you want two different dead keys to enter the same dead key state, you need to know the name so that you can enter it at the appropriate time. Again, if you have multi-level dead keys, you need to know the names of the states involved.