MiFi stands for "my Wi-Fi" and is pronounced as "my-Fi."
MiFi is a portable broadband wireless device that combines functions of a router, modem and access point usually about the size of a credit card.
Also known as a personal hotspot. MiFi was designed to simplify setting up of small local area networks (LAN), or an ad-hoc network. MiFi devices support up to five users and can also network Wi-Fi-capable devices including cell phones, digital cameras, notebooks, MP3 players and gaming systems. A MiFi device gets Internet connection almost anywhere with cellular connectivity.
I just got a MiFi hook up and it works great.