It can be deduced that court packing simply means they idea of adding justices to the Supreme Court.
Packing the courts has to do with the addition of justices to the lower courts or the Supreme courts in order to shift the balance in a liberal, conservative, or other direction.
It should be noted that it was President Franklin's idea to expand the size of the Supreme Court. This wasn't passed by Congress as it was believed that the president was getting too much power.
