A device is any object that performs a function or helps in the performance of a task. In a scientific or technological context, a device is usually an instrument used to measure, record, or control physical quantities such as temperature, light intensity, flow rate, chemical concentration, weight, force, speed etc.
In physics and engineering sciences, devices are often named after their inventors (e.g., Ampere’s law) or after their intended use (e.g., electron microscope). Many devices make use of electronics to perform their function (e.g., electronic thermometer), while others may be purely mechanical (e.g., windmill).
The term “device” can also refer to software programs running on computers which provide some sort of output or result (e.g., word processing software).
A wide variety of devices have been invented over the centuries to perform various tasks; some are very simple while others are extremely complex. The study and development of devices is a major focus of many disciplines including physics, electrical engineering and mechanical engineering.