diff --git a/capi/geos_c.cpp b/capi/geos_c.cpp
index ab889455c4..834f3ef51c 100644
--- a/capi/geos_c.cpp
+++ b/capi/geos_c.cpp
@@ -213,15 +213,15 @@ extern "C" {
 //------------------------------------------------------------------
 
     char
-    GEOSRelatePattern(const Geometry* g1, const Geometry* g2, const char* pat)
+    GEOSRelatePattern(const Geometry* g1, const Geometry* g2, const char* imPattern)
     {
-        return GEOSRelatePattern_r(handle, g1, g2, pat);
+        return GEOSRelatePattern_r(handle, g1, g2, imPattern);
     }
 
     char
-    GEOSRelatePatternMatch(const char* mat, const char* pat)
+    GEOSRelatePatternMatch(const char* intMatrix, const char* imPattern)
     {
-        return GEOSRelatePatternMatch_r(handle, mat, pat);
+        return GEOSRelatePatternMatch_r(handle, intMatrix, imPattern);
     }
 
     char*
@@ -1610,9 +1610,9 @@ extern "C" {
     }
 
     char
-    GEOSPreparedRelatePattern(const geos::geom::prep::PreparedGeometry* pg1, const Geometry* g2, const char* pat)
+    GEOSPreparedRelatePattern(const geos::geom::prep::PreparedGeometry* pg1, const Geometry* g2, const char* imPattern)
     {
-        return GEOSPreparedRelatePattern_r(handle, pg1, g2, pat);
+        return GEOSPreparedRelatePattern_r(handle, pg1, g2, imPattern);
     }
 
     CoordinateSequence*
diff --git a/capi/geos_c.h.in b/capi/geos_c.h.in
index 77ada433a6..e274a257da 100644
--- a/capi/geos_c.h.in
+++ b/capi/geos_c.h.in
@@ -1430,7 +1430,7 @@ extern char GEOS_DLL GEOSRelatePattern_r(
     GEOSContextHandle_t handle,
     const GEOSGeometry* g1,
     const GEOSGeometry* g2,
-    const char *pat);
+    const char *imPattern);
 
 /** \see GEOSRelate */
 extern char GEOS_DLL *GEOSRelate_r(
@@ -1441,8 +1441,8 @@ extern char GEOS_DLL *GEOSRelate_r(
 /** \see GEOSRelatePatternMatch */
 extern char GEOS_DLL GEOSRelatePatternMatch_r(
     GEOSContextHandle_t handle,
-    const char *mat,
-    const char *pat);
+    const char *intMatrix,
+    const char *imPattern);
 
 /** \see GEOSRelateBoundaryNodeRule */
 extern char GEOS_DLL *GEOSRelateBoundaryNodeRule_r(
@@ -4935,14 +4935,14 @@ extern char GEOS_DLL GEOSEqualsIdentical(
 * \see geos::geom::Geometry::relate
 * \param g1 First geometry in pair
 * \param g2 Second geometry in pair
-* \param pat DE9IM pattern to check
+* \param imPattern DE9IM pattern to check
 * \return 1 on true, 0 on false, 2 on exception
 * \since 2.2
 */
 extern char GEOS_DLL GEOSRelatePattern(
     const GEOSGeometry* g1,
     const GEOSGeometry* g2,
-    const char *pat);
+    const char *imPattern);
 
 /**
 * Calculate and return the DE9IM pattern for this geometry pair.
@@ -4960,15 +4960,15 @@ extern char GEOS_DLL *GEOSRelate(
 /**
 * Compare two DE9IM patterns and return true if they
 * are consistent.
-* \param mat Complete DE9IM string (does not have "*")
-* \param pat Pattern to match to (may contain "*")
+* \param intMatrix Complete DE9IM string (does not have "*")
+* \param imPattern Pattern to match to (may contain "*")
 * \return 1 on true, 0 on false, 2 on exception
 *
 * \since 3.3
 */
 extern char GEOS_DLL GEOSRelatePatternMatch(
-    const char *mat,
-    const char *pat);
+    const char *intMatrix,
+    const char *imPattern);
 
 /**
 * Calculate and return the DE9IM pattern for this geometry pair.
@@ -5226,7 +5226,7 @@ extern char GEOS_DLL * GEOSPreparedRelate(
 * prepared and provided geometry.
 * \param pg1 The prepared geometry
 * \param g2 The geometry to test
-* \param pat The DE9IM pattern to test
+* \param imPattern The DE9IM pattern to test
 * \returns 1 on true, 0 on false, 2 on exception
 * \see GEOSPrepare
 * \see GEOSRelatePattern
@@ -5237,7 +5237,7 @@ extern char GEOS_DLL * GEOSPreparedRelate(
 extern char GEOS_DLL GEOSPreparedRelatePattern(
     const GEOSPreparedGeometry* pg1,
     const GEOSGeometry* g2,
-    const char* pat);
+    const char* imPattern);
 
 /**
 * Use a \ref GEOSPreparedGeometry do a high performance
diff --git a/capi/geos_ts_c.cpp b/capi/geos_ts_c.cpp
index 37b00020ee..2ac48477c0 100644
--- a/capi/geos_ts_c.cpp
+++ b/capi/geos_ts_c.cpp
@@ -665,23 +665,23 @@ extern "C" {
 //------------------------------------------------------------------
 
     char
-    GEOSRelatePattern_r(GEOSContextHandle_t extHandle, const Geometry* g1, const Geometry* g2, const char* pat)
+    GEOSRelatePattern_r(GEOSContextHandle_t extHandle, const Geometry* g1, const Geometry* g2, const char* imPattern)
     {
         return execute(extHandle, 2, [&]() {
-            std::string s(pat);
+            std::string s(imPattern);
             return g1->relate(g2, s);
         });
     }
 
     char
-    GEOSRelatePatternMatch_r(GEOSContextHandle_t extHandle, const char* mat,
-                             const char* pat)
+    GEOSRelatePatternMatch_r(GEOSContextHandle_t extHandle, const char* intMatrix,
+                             const char* imPattern)
     {
         return execute(extHandle, 2, [&]() {
             using geos::geom::IntersectionMatrix;
 
-            std::string m(mat);
-            std::string p(pat);
+            std::string m(intMatrix);
+            std::string p(imPattern);
             IntersectionMatrix im(m);
 
             return im.matches(p);
@@ -3761,10 +3761,10 @@ extern "C" {
 
     char
     GEOSPreparedRelatePattern_r(GEOSContextHandle_t extHandle,
-                         const geos::geom::prep::PreparedGeometry* pg, const Geometry* g, const char* pat)
+                         const geos::geom::prep::PreparedGeometry* pg, const Geometry* g, const char* imPattern)
     {
         return execute(extHandle, 2, [&]() {
-            return pg->relate(g, std::string(pat));
+            return pg->relate(g, std::string(imPattern));
         });
     }