Libre software is a term for free software. The adjective libre is a word from the Spanish and French languages which means "has freedom".
The European Commission coined this term in 2000. Like other alternative terms for free software, the main motivation was to avoid the confusing ambiguity of the English adjective free.
While the English adjective free can mean either "no price" or "unfettered", libre only means the latter: "unfettered", or "possessing freedom". The adjective libre compliments the word gratis, from Spanish, or gratuit from French. Those two terms are used to describe commodities that are "free of charge".
The acronym FOSS (Free and Open Source Software) is expanded by some to represent the word "libre": FLOSS (Free/Libre/Open-Source Software).
However, the term libre software is not completely unambiguous. In Tagalog, the adjective libre is ambiguous in the same way that free is in English. In the Philippines, therefore, malayang software is the preferred term for free software.