What is a microcontroller, pic, 8 bit Microcontroller, programming microcontroller

Microcontroller manufacturers and programmable 8 bit microcontrollers. Wireless, usb, lcd, pic, embedded and low power 8 bit microcontrollers. what is an 8 bit microcontroller and its programming software. 

https://www.futureelectronics.com/p/semiconductors--microcontrollers--8-bit/pic18lf452-i-l-microchip-2490043