Acronym: Free Libre Open Source Software
Aka: Free Open Source Software
A term meaning: both Free Software as Well as Open-Source software. The L of Libre is evaded by some while included by others.
It is commonly used to to take ingredients from both Free Software and Open-Source software or their respective philosophies. It is useful to evade a flame war because one of the 2 terms was left out while applicable or to make an accurate point which involves both philosophies or compatible licenses.