In physics and engineering, measurement is the activity of comparing physical quantities of real-world objects and events. Established standard objects and events are used as units, and the measurement results in a given number for the relationship between the item under study and the referenced unit of measurement. Measuring Instruments are the means by which this translation is made.
For example, the unit for length might be a well-known person's foot, and the length of a boat can be given as the number of times that person's foot would fit the length of the boat. The history of measurements is a topic within the History of Science and Technology. The meter was standardized as the unit for length after the French revolution, and has since been adopted all over Europe.