Are there any symbols, emoji or not, that have unequivocal meaning? I recall the discussion around creating the symbol for "radioactive", and the challenges aro

Are there any symbols, emoji or not, that have unequivocal meaning? I recall the discussion around creating the symbol for "radioactive", and the challenges around making a symbol that would convey that meaning for thousands of years: https://web.archive.org/web/20090328112312/http://www.wipp.energy.gov/picsprog/articles/wipp%20exhibit%20message%20to%2012,000%20a_d.htm https://web.archive.org/web/20090328112312/http://www.wipp.e... (original on energy.gov is gone)