As of late I have seen a few threads where the OP is in need of dire help and their general lack of understanding about Terminology / Technology, and as people trying to help them we are struggling to understand what they mean so hopefully this thread will help them help us, to help them.
I'll be using wikipedia for most of the links unless they don't have any.
Feel free to add others that I havn't and I will add them to this main list
Home Theater Terminology
AMP = http://en.wikipedia.org/wiki/Amplifier
HDMI = High-Definition Multimedia Interface http://en.wikipedia.org/wiki/HDMI
Projector = http://en.wikipedia.org/wiki/Image_projector
AVR = http://en.wikipedia.org/wiki/AV_receiver
PVR/ DVR = http://en.wikipedia.org/wiki/Digital_video_recorder
HTPC = http://en.wikipedia.org/wiki/HTPC
HD vs FullHD = http://www.getprice.com.au/blog-hd-read ... erence.htm
MRA = Multi Room Audio http://smarthouse.com.au/Automation/Sound/G5M2F8N6
Home Networking/ Telephony
PSTN = http://en.wikipedia.org/wiki/PSTN or Plain Simple Telephone Network
POTS = http://en.wikipedia.org/wiki/Plain_old_ ... ne_service
ADSL = The most common form of Internet Connection in Australia: http://en.wikipedia.org/wiki/ADSL
ADSL Modem = A Digital Subscriber Line (DSL) modem is a device used to connect a computer or router to a telephone circuit that has Digital Subscriber Line service configured: http://en.wikipedia.org/wiki/ADSL_modem
FTTH aka FTTP = Fibre to the Home / Premisis http://en.wikipedia.org/wiki/FTTH
ONT = FTTH "Modem/Interface" Like a Router has up to 4 network outputs which can be their own Internet Connections (4 Different providers) and has 2 PSTN Connections for Phone outputs on two different providers.
HFC aka Foxtel/ Optus Cable (used only by these two carriers) for Wired "Pay tv" and or Cable Broadband http://en.wikipedia.org/wiki/Hybrid_fiber-coaxial
NBN aka NBNCo = National Broadband Network aka FTTH http://www.nbnco.com.au/
Router = A router is a device that forwards data packets across computer networks. http://en.wikipedia.org/wiki/Router
Network Switch = http://en.wikipedia.org/wiki/Network_switch
Other Technology
VoIP = Voice over Internet Protocol http://en.wikipedia.org/wiki/VoIP
IP TV = Internet Protocol Television http://en.wikipedia.org/wiki/IP_TV Fetch TV is a form of this
Network Hardware/ Devices
Patch Panel = http://en.wikipedia.org/wiki/Patch_panel
Rack Mount = http://en.wikipedia.org/wiki/Rack_mount
NAS = http://en.wikipedia.org/wiki/Network-attached_storage
HFS= Home File Server slightly more intelligent then a simple NAS http://en.wikipedia.org/wiki/Home_server
Structured Cabling = http://en.wikipedia.org/wiki/Structured_cabling