Ghost notes and dead notes

Recently, I have seen tabs for a few songs that have both "dead notes" (marked with X's) and "ghost notes" (the fret number is in parentheses). I have looked online to find out what the difference was between them and I haven't been able to come up with a definitive answer. Does anyone know what the difference is?
Also, one website I found told me that you play ghost notes by lightly pressing your finger on the string and strumming, much like you would a harmonic. However, the tabs I was looking at had ghost notes on the third and fifth frets, which are frets you would play harmonics on. Another song had an open A ghost note (that tab was for guitar and not bass, but still). How would you play ghost notes on frets that produce harmonics? What about on open strings? Thanks!

I never really was sure what ghost notes meant. You know what dead notes are I'm sure, as for ghost notes I always understood them as kind "hidden notes". They are there, they persist, but are not as prominent as regular notes. I'd say, try to play them like regular notes, but lightly. I hardly run into ghost notes and when I do I find that they take care of themselves in a way. Sometimes I play them while not muting the main line...it all depends.
Think of them as hidden notes that you play discretely.
Also if you listen to the song or watch a cover of it, you may see how others tackle the notes.

So they're just quieter/less emphasized notes? Finally I know the answer! Thanks stryfer

the note in brackets on tabs () are usually notes that are either not played by the original bassist but the person writing the tab feels they should be there
or jus notes that arent as important harmony wise and can be left out or played quietly