If you want the dictionary definition, just double click on any word.
... or
neither ... nor

When choosing, either .. or can be used to show there is a choice between two different things, but you can only choose one, not both.

For example:-

You can have either beer or wine.

You can use either ... or to give someone an ultimatum.

For example:-

Either you leave now or I'll tell your wife!

neither ... nor is a construction we use to show that two or more things are not true or possible.

For example:-

He drinks neither wine nor beer.

See also either / as well / too
See also not either vs neither