ESP8266 is a Wi-Fi chip manufactured by Espressif Systems.
It is used in a variety of Wi-Fi modules, most of them being named ESP-XX (XX representing numerics) and developed by AI-Thinker. These Wi-Fi modules are in turn part of different Wi-Fi boards/modules, but can also be used stand-alone.
The term ESP telemetry module is used for modules that have been flashed with the MavESP8266 firmware.
