Purpose of 2>&1 in the command

Shell Programming and Scripting
1

Can any body kindly tell me what is the purpose of 2>&1 in the following commands.

nohup ./append_import.sh 1 > import1.out 2>&1 < /dev/null &
nohup ./append_import.sh 2 > import2.out 2>&1 < /dev/null &

2

Redirect Standard error to CURRENT standard output(which could be file or /dev/null) ..