Image by Army.mil via Flickr5G war (n.) - Also known as 5GW, fifthgen war or fifth generation modern warfare. Any of several theoretical successors to fourth-generation modern warfare, which describes the primary strategies and tactics of a new type of conflict, particularly one that is indisputably superior to the previous generation. It is becoming the preferred buzzword for imagined futuristic conflicts, supplanting previous trope-words like hyperwar or infowar.
What exactly constitutes 5G War is up for debate, which is part of the reason it's slowly starting to catch on in the sci-fi set, as it can give the appearance of authenticity to a mil-SF work without actually contradicting any canonically established sources. 5G war is generally imagined to involve guerilla tactics enhanced by modern consumer communications technology and/or cyberattacks, but it's a good bet that as other techno-fads come and go, they'll make appearances under the 5G war banner as well.
I bring it up because: Friday is the eighth anniversary of the September 11th attacks, which thrust the concept of fourth generation, assymetric warfare into the public consciousness. As the world continues to grapple with the various implications of that tragedy, science fiction does likewise, helping us prepare for future conflicts by imagining impossible ones.