https://blog.hackster.io/picking-the-right-arduino-341a0a9550c7

My introduction to the Arduino happened when there were two options: the Duemilanove and the Mega. The only decision involved the number of I/O pins. Almost ten years later, there is an Arduino board type for (practically) every application or project. The choice can be overwhelming when selecting. Here are some considerations for the major types.

Arduino is an open source hardware platform. There are two elements to the name: the boards and the software. Only boards from Arduino.cc can officially be called an “Arduino.” (The name is trademarked.) From an open source perspective, as Arduino grew in popularity the Software, or Integrated Development Environment (IDE), has been expanded to support many other boards. These devices are more correctly called “Arduino compatibles.”