The acronym "WBO" most commonly stands for the World Boxing Organization, which is one of the four major organizations that sanction professional boxing bouts worldwide. It was founded in 1988 and is recognized as a major sanctioning body alongside the WBA, WBC, and IBF.

Besides this, "WBO" can have other meanings depending on context, such as Woman Business Owner, West Bay Opera, World Bamboo Organization, and also as informal internet/text slang meaning "I won't be online".

If the context is sports or boxing, "WBO" almost certainly refers to the World Boxing Organization. In casual messaging, it might mean "I won't be online." Let me know if a specific context is needed for further detail.