tethered jailbreak? what does it mean?

[mightyPhone]

Hi I keep seeing the say that redsn0w is a ethered jailbreak, furthermore, it says after jb withe redsn0w, to reboot , it has to be tethered. But I have jbed using redsn0w, when I need to rebbot, I don't have to do anything, I just reboot it like a normal iPhone, no tether what so ever, So what does tethered jailbreak really mean? Did I misunderstand something?

[sLi]

Once you jailbreak your phone for the first time (tethered[or untethered]) it changes various files.

after doing this when you turn your phone off and try and turn it back on, because its tethered (ie. it needs redsn0w to boot it via ?bootrom? exploit) the phone says "hey these files arent what they are supposed to be, im not turning on"

an untethered jailbreak uses an exploit to allow the hacked ?bootrom? to persist though power cycles

(I'm sure someone will correct me on the terminology I used, but essentially thats how it woks)