diff --git a/pyomo/contrib/pyros/config.py b/pyomo/contrib/pyros/config.py
index fca42e78cbd..217172ce012 100644
--- a/pyomo/contrib/pyros/config.py
+++ b/pyomo/contrib/pyros/config.py
@@ -212,7 +212,7 @@ def domain_name(self):
         """Return str briefly describing domain encompassed by self."""
         cdt = _domain_name(self.cdatatype)
         ct = _domain_name(self.ctype)
-        return f"{cdt}, {ct}, or Iterable[{cdt}/{ct}"
+        return f"{cdt}, {ct}, or Iterable[{cdt}/{ct}]"
 
 
 class SolverNotResolvable(PyomoException):