移動通信

5G: the fifth generation of mobile communication technology is expected to be introduced in Japan by 2020, offering faster transmission and the ability to send and receive up to 1,000 times more data than 4G:

スマホなどで使われる第5世代移動通信方式の略称。4Gより通信速度が速く、1000倍もの大容量データの送受信が可能になります。

The same word comes up again over a year later — see the September 2019 entry, on how the technology changes roughly every decade.