What does "2>&1" do in command line?

What does "2>&1" do in command line? I know that the > sign is used for output redirection in the command line, but I'm having trouble finding something that explains the use of 2>&1 in the command line. For example:
Asked by: Guest \| Views: 496

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Guest [Entry]

"The 1 denotes standard output (stdout). The 2 denotes standard error (stderr).

So 2>&1 says to send standard error to where ever standard output is being redirected as well. Which since it's being sent to /dev/null is akin to ignoring any output at all."

Guest [Entry]

2 refers to STDERR. 2>&1 will send STDERR to the same location as 1 (STDOUT).