Bricking - breaking your device in a way that makes it as useful as a brick
apk - basically a .exe for android
overclocking - increasing the speed of a device
sdk - software development kit
undervolting - decreasing voltage to something
rooting or root or rooted - root is a user in Linux with the ability to affect everything on a system, including files that if edited could seriously damage(brick) your device.
sideloading - loading an application(.apk file) though USB, dropbox, email, etc. and installing from there instead of installing from a market.
xda -
http://www.xda-developers.com/ - a community of people that spend a lot of time developing/hacking on phones, tablets, etc. No real eDGe community there though, yet.
I hope this answers your questions, most of the time, however, if you don't know what one of the terms means you should likely do some more research about what you are doing before proceeding, when developing on a device like this(especially without warranty or official support), it can be very risky to attempt any of the above(except sideloading and visiting xda of course lol).