The International Organization for Standardization is to standards organizations worldwide what the UN is to the national governments.
Although ISO works as an acronym in some languages, their website claims the name is really derived from the Greek word isos.
From an open source perspective, the ISO unfortunately is an old-economy standardization organisation, i.e., they won't let you read their publications unless you buy them. Standards effectively available from other sources includes
LV: Some people also use ISO as an abbreviation for "In Search Of", as in "ISO: cross platform games written in Tcl/Tk"...