Update docs/glossary/index.md

Co-authored-by: Philipp Ahmann <[email protected]>

Author: simone-weiss

docs/glossary/index.md

@@ -43,6 +43,7 @@ Please note:
 | Safety analysis | |
 | Safety case | |
 | Safety element out of context | |
+| Safety integrity standard | |
 | Safety life cycle |
 | Safety manual | |
 | Safety mitigation | |