What is a LED driver, LED Driver Modules, led constant current driver circuit

 100 - 277Vac, 55W, 100 - 1800mA, 18-54V, [0-10V], IP66 LED Driver

https://www.futureelectronics.com/p/semiconductors--Led-lighting-components--led-driver-modules-rev--constant-current-acdc-led-drivers/xi055c180v054bsj1-signify-north-america-1084261