This is a guide to help you understand the basic terms use in the Jailbreak and what they mean and their purposes. This is not a guide to teach you how to jailbreak your device, this guide will just help you understand most of the basic terms use regarding to jailbreak.
Activation:
Activation/Activating is the process of bypassing the “Emergency Call Screen” to access the SpringBoard of the iPhone, this is not the same as unlocking.
Baseband:
This is the device in the iPhone that manages all the functions which require an antenna.
Blackra1n:
This is Geohot’s method for jailbreaking iOS 3.1, 3.1.1 and 3.1.2 on all Devices. BlackRa1n also unlocks and hacktivates the iPhone 3G and 3GS running baseband 05.11.07.
Blacksn0w:
Geohot’s unlock and hacktivate for the iPhone 3G and 3GS running baseband 05.11.07.
Bootrom:
This is the first code that runs on your iDevice.
Cydia:
Unofficial App Store. There you will find apps rejected by Apple in the official app store, themes, tweaks, every coll stuff.
DFU Mode:
Device Firmware Upgrade. Allows all devices to be restored from any state.
F0recast:
F0recast is an application created by iH8sn0w. This tool will tell you IDevice firmware installed, baseband etc.
Greenpois0n:
Jailbreak method from Chronic Dev Team.
iReb:
Tool from iH8sn0w to allow iTunes to accept custom IPSW firmware.
Star/Jailbreakme.com:
Jailbreak from Comex that will jailbreak your iDevice directrly from the safari.
SSH:
Accessing iDevice files from the computer.
Tethered Jailbreak:
Jailbreak that requires to use the Jailbreaking tool you use to jailbreak the device so it could boot up again after turn in off.
Ultrasnow:
Unlock for unlock-able baseband firmware from various iPhone Dev Team.
Untethered jailbreak:
Jailbreak that doesn’t requires rejailbreaking the device so it could boot-up again after turning the device off.
You can find all information regarting to jailbreaks at: http://theiphonewiki.com/wiki/index.php?title=Main_Page