What does limited or unlimited mean in a license? For example how is a limited license to use a program or specific source code, different than an unlimited one?
A limited license normally contains limits in the scope of use you may make of intellectual property (geographical or in type of use), in the extent to which it can be sublicensed, in the people who may use it pursuant to the license, and/or in the duration during which one may use it. Most licenses for intellectual property are limited.
An unlimited license (which is very rare) would be a right to use intellectual property without limitation in the same manner as a true owner of the intellectual property rights in question.