Frequently Asked Questions about the GNU Licenses - GNU Project - Free Software Foundation What does it mean to say a license is “compatible with the GPL?” (#WhatDoesCompatMean)
What does "the Program" mean in GPLv3? - GNU Project - Free Software Foundation https://www.gnu.org/licenses/gplv3-the-program.html
Is BSD more free than GPL Depends on your perspective. From the point of view of someone who is not the original author (or the copyright holder, if they are not the same) then BSD is more free. You can do what you want with the code. But for the author/copyright holder, GPL has an advantage that noone can take your code and improve it without the changes being available to you. If I were releasing code under a free licence, I would choose the GPL. If I were using someone elses code to incorporate into a commercial product, I'd prefer it be under the BSDL.