The International System of Units states that entropy has a unit of Joules/Kelvin. It always has the dimensions of energy divided by temperature and can be measured in a myriad of units as long as they fit that criteria.
Entropy is defined as the disorder of a system. It is a thermodynamic term that measures the number of ways a thermodynamic system may be arranged. The measurement is a state function and thus its value only depends on the initial entropy and the final entropy of the system. In thermodynamics, entropy can never decrease and is always increasing. In turn, thermodynamic systems are constantly evolving to adapt to an ever-changing state of entropy.