Arduino is an open-source set of hardware and software used to build interactive electronics projects. Applications for Arduino are typically written in C++ in the Arduino IDE or Arduino Web Editor (recommended over Arduino IDE); however other options for controlling Arduinos exist such as with Node-RED.
Deeper Knowledge on Arduino
The open-source electronics platform for interactive projects and prototypes
Knowledge about programming Arduino boards
Broader Topics Related to Arduino
Build and deconstruct electrically powered devices
Information and resources about open-source