What is the difference between lockout and tagout?

What is the difference between lockout and tagout?
While often intermingled, the terms “lockout” and “tagout” are not interchangeable.

Lockout
Lockout occurs when an energy source (electrical, mechanical, hydraulic, pneumatic, chemical, thermal or other) is physically isolated from the system that uses it (a machine, equipment or process). This is done using a variety of lockout padlocks and devices best suited for specific applications.

Tagout
Tagout is the process of affixing a label, or tag, that communicates information about what’s being done to the machine or equipment and why it’s important. Details on a tag may include:

DANGER or WARNING label
Instructions (e.g., Do Not Operate)
Purpose (e.g., Equipment Maintenance)
Timing
Name and / or photo of the authorized worker
Image of a Safety Tag Station on a wall with many tags in it
Tagout alone is not recommended as it does not provide a physical means to prevent equipment from re-energizing. Since the inception of the lockout tagout standard in 1989, energy isolation points have been modified or replaced to allow for padlock placement, and new devices have been developed to retrofit energy sources to help meet the standard.

When used together by affixing a tag to a padlock, lockout and tagout provide enhanced protection for workers against re-energization.