What does NN stand for?

What does NN mean?

NN	No No Governmental » Military
NN	Neural Network Academic & Science » Electronics
NN	Neural Network Computing » Networking
NN	Noch Nicht Miscellaneous » Unclassified
NN	Nearest Neighbor Computing » Networking
NN	Nearest Neighbor Academic & Science » Chemistry
NN	Nearest Neighbor Academic & Science » Electronics
NN	Neonatal Medical » Physiology
NN	Nerves Medical » Physiology
NN	Nearest Neighbors Academic & Science » Mathematics
NN	Netscape Navigator Computing » Software
NN	Not Null Computing » General
NN	No Notice Community » Law
NN	No Name Miscellaneous » Unclassified
NN	No News Internet » Chat
NN	Nearest Neighbour Miscellaneous » Unclassified
NN	Non Nuclear Governmental » Military
NN	No Names Community » Law
NN	Next New Internet » Chat
NN	Nearest Neighbours Miscellaneous » Unclassified
NN	Nomen Nescio Academic & Science » Universities
NN	Nano- Crystal Academic & Science » Chemistry
NN	Netscreen News Community » Media
NN	Numismatic News Miscellaneous » Coins
NN	Night Night Internet » Chat