A LoraWAN Gateway is a device that receives (and potentially sends) the wireless data from your lora enabled sensors, and then connects it to the Internet.
These sensors are typically low powered devices capable of detecting such things as moisture of the soil, pollution levels, or pretty much whatever you wish to measure.
The LoraWAN Gateway can be connected to the Internet in a variety of ways, such as Ethernet, 3G,4G and 4G LTE.
Manufacturers include Link-Labs, MultiTech and Kerlink
LORA itself is a low power network technology that is an alternative technology to other standards such as Sigfox.