diff --git a/gtsam/geometry/Similarity3.cpp b/gtsam/geometry/Similarity3.cpp
index 5cb1466b4..b086a5b5c 100644
--- a/gtsam/geometry/Similarity3.cpp
+++ b/gtsam/geometry/Similarity3.cpp
@@ -24,7 +24,6 @@
 namespace gtsam {
 
 using std::vector;
-typedef vector<Point3Pair> PointPairs;
 
 namespace {
 /// Subtract centroids from point pairs.
diff --git a/gtsam/geometry/Similarity3.h b/gtsam/geometry/Similarity3.h
index b82862ddb..79180985d 100644
--- a/gtsam/geometry/Similarity3.h
+++ b/gtsam/geometry/Similarity3.h
@@ -30,6 +30,8 @@ namespace gtsam {
 // Forward declarations
 class Pose3;
 
+typedef std::vector<Point3Pair> PointPairs;
+
 /**
  * 3D similarity transform
  */