Well, ok, if all OP wanted to know is what a copyright license is:
By default, copyright law in most countries prohibits anyone except the author or other copyright holder from distributing creative works, including software, even in modified form. There are a few exceptions to this, but this is the general rule.
A license is a document that the copyright holder agreed to that grants someone permission to do so anyway.
In the context of open source, such a license needs to meet certain conditions to be considered open source. Among other things it needs to allow anyone (not just specific licensees) to distribute the software for any purpose, even in modified form.
Well, ok, if all OP wanted to know is what a copyright license is:
By default, copyright law in most countries prohibits anyone except the author or other copyright holder from distributing creative works, including software, even in modified form. There are a few exceptions to this, but this is the general rule.
A license is a document that the copyright holder agreed to that grants someone permission to do so anyway.
In the context of open source, such a license needs to meet certain conditions to be considered open source. Among other things it needs to allow anyone (not just specific licensees) to distribute the software for any purpose, even in modified form.