Aperture 5 : Any opening in the protective housing or other enclosure of a laser product through which laser or collateral radiation is emitted thereby allowing human access to such radiation
US Department of Labor, Hospital eTool: Glossary OSHA, Occupational Safety & Health Administration OSHA, Washington, D.C., USA 2010. https://www.osha.gov/SLTC/etools/hospital/glossary .html, (OSHA/ Hospital - Amer) {616}