Define the term unit in physics.

1. In Physics, the term unit refers to the quantity of a constant magnitude, used to measure the magnitudes of other quantities of an identical type.
2. The magnitude of a physical quantity is given by the formulae:
3. $Physicalquantity=(numericalvalue)\times \left(unit\right)$.
4. A unit should not change with the change in time or physical conditions like temperature and pressure.
5. It should be accurately defined.
6. It should be easily reproducible and available.