diff --git a/src/include/TransitionMatrix.h b/src/include/TransitionMatrix.h
index 9180fabaea8c937227d5574ea0a821ee9a82f2aa..25e5cf86b0b5b3a801bca5db26e274c510f7e748 100644
--- a/src/include/TransitionMatrix.h
+++ b/src/include/TransitionMatrix.h
@@ -164,9 +164,9 @@ class TransitionMatrix {
   
   /*! \brief Test whether two instances of TransitionMatrix are equal.
    *
-   * Transition matrixes can be the result of a calculation or of a file input operation,
+   * Transition matrices can be the result of a calculation or of a file input operation,
    * reading from a previously computed object. The `==` operator tests for the equivalence
-   * of two transition matrixes, returning `true` if they are equivalnet, `false` otherwise.
+   * of two transition matrices, returning `true` if they are equivalnet, `false` otherwise.
    *
    * \param other: `TransitionMatrix &` Reference to the instance to be compared with.
    * \return result: `bool` True, if the two instances are equal, false otherwise.
diff --git a/src/testing/test_TTMS.cpp b/src/testing/test_TTMS.cpp
index bdf0daaedc510a210ac1e314f69cf93b91a36f88..3b054359c0ef366f74b9f10b5b023f0bca45f7f4 100644
--- a/src/testing/test_TTMS.cpp
+++ b/src/testing/test_TTMS.cpp
@@ -35,9 +35,9 @@ int main(int argc, char **argv) {
   }
   a = TransitionMatrix::from_binary(legacy_file);
   b = TransitionMatrix::from_binary(hdf5_file, "HDF5");
-  if (*a == *b) printf("Transition matrixes a and b are equal.\n");
+  if (*a == *b) printf("Transition matrices a and b are equal.\n");
   else {
-    printf("Transition matrixes a and b are different.\n");
+    printf("Transition matrices a and b are different.\n");
     result = 1;
   }
   return result;