Arduino is an open-source prototyping platform based on hardware and software.
Arduino boards are developed by the company that shares the same name, Arduino.
The board have no operating system, and CPUs range between AVR, ARM Cortex and Intel Quark. Storage is flash memory and EEPROM. Memory is SRAM.
The boards have been used for all sort of applications, from IoT smart things to more complex scientific instruments.
The company has also developed its own software, named Arduino Software IDE written in Java, C and C++.