`which export` not showing path of the executable

When I run which export I get the following output:

Code:[root@localhost abc]# which export
/usr/bin/which: no export in (/usr/local/bin:/usr/local/sbin:/usr/bin:/usr/sbin:/root/bin)However, I am successfully able to run the following command

Code:export PATH=$PATH:/tmpMy question why I am able to run the export command successfully even the export command is not defined in the PATH variable