"Another misunderstanding of “open source” is the idea that it means “not using the GNU GPL.” This tends to accompany another misunderstanding that “free software” means “GPL-covered software.” These are both mistaken, since the GNU GPL qualifies as an open source license and most of the open source licenses qualify as free software licenses. There are many free software licenses aside from the GNU GPL."
The Open Source Initiative sees the GPL as Open Source, and the Free Software Foundation sees the ISC (OpenBSD license) as Free Software. Neither group's definition depends on if it is copyleft of permissive.
The main difference between Free Software and Open Software is what aspect of the software they focus on. Free Software is more on the freedom while Open Source is more on the development method. They still value the other aspects, just not as strongly.
"Another misunderstanding of “open source” is the idea that it means “not using the GNU GPL.” This tends to accompany another misunderstanding that “free software” means “GPL-covered software.” These are both mistaken, since the GNU GPL qualifies as an open source license and most of the open source licenses qualify as free software licenses. There are many free software licenses aside from the GNU GPL."
The Open Source Initiative sees the GPL as Open Source, and the Free Software Foundation sees the ISC (OpenBSD license) as Free Software. Neither group's definition depends on if it is copyleft of permissive.