What is the difference between lockout and tagout?

The two devices have very similar effects, but are very different when it comes to a flourishing LOTO program

All LOTO programs are aware of the two terms lockout and tagout, but what's the fundamental difference between the two? 

Lockout refers to a device that holds hazardous energy in isolation and prevent machines from being energized with physical restraints in which cannot be removed without a key. 

Tagout devices warn employees against reenergizing while it is being serviced. They are simply much easier to remove, and a result, do not offer the same level of protection.