diff --git a/include/openmc/nuclide.h b/include/openmc/nuclide.h
index 68742d5b1..ae4cdda1e 100644
--- a/include/openmc/nuclide.h
+++ b/include/openmc/nuclide.h
@@ -58,7 +58,7 @@ public:
   //! from probability tables.
   void calculate_urr_xs(int i_temp, Particle& p) const;
 
-  double one_group_xs(int MT, gsl::span<const double> energy, gsl::span<const double> flux) const;
+  double collapse_rate(int MT, gsl::span<const double> energy, gsl::span<const double> flux) const;
 
   // Data members
   std::string name_; //!< Name of nuclide, e.g. "U235"
diff --git a/include/openmc/reaction.h b/include/openmc/reaction.h
index c0cb767ec..ad1e7702c 100644
--- a/include/openmc/reaction.h
+++ b/include/openmc/reaction.h
@@ -27,7 +27,7 @@ public:
   //! \param[in] temperatures Desired temperatures for cross sections
   explicit Reaction(hid_t group, const std::vector<int>& temperatures);
 
-  double one_group_xs(gsl::span<const double> energy, gsl::span<const double> flux, const std::vector<double>& grid) const;
+  double collapse_rate(gsl::span<const double> energy, gsl::span<const double> flux, const std::vector<double>& grid) const;
 
   //! Cross section at a single temperature
   struct TemperatureXS {
diff --git a/openmc/lib/nuclide.py b/openmc/lib/nuclide.py
index 4dd90f9ca..0e3ca66eb 100644
--- a/openmc/lib/nuclide.py
+++ b/openmc/lib/nuclide.py
@@ -25,7 +25,7 @@ _dll.openmc_load_nuclide.errcheck = _error_handler
 _dll.openmc_nuclide_name.argtypes = [c_int, POINTER(c_char_p)]
 _dll.openmc_nuclide_name.restype = c_int
 _dll.openmc_nuclide_name.errcheck = _error_handler
-_dll.openmc_nuclide_one_group_xs.argtypes = [c_int, c_int, _array_1d_dble,
+_dll.openmc_nuclide_collapse_rate.argtypes = [c_int, c_int, _array_1d_dble,
     _array_1d_dble, c_int, POINTER(c_double)]
 _dll.nuclides_size.restype = c_size_t
 
@@ -77,11 +77,11 @@ class Nuclide(_FortranObject):
         _dll.openmc_nuclide_name(self._index, name)
         return name.value.decode()
 
-    def one_group_xs(self, MT, energy, flux):
+    def collapse_rate(self, MT, energy, flux):
         energy = np.asarray(energy, dtype=float)
         flux = np.asarray(flux, dtype=float)
         xs = c_double()
-        _dll.openmc_nuclide_one_group_xs(self._index, MT, energy, flux, len(flux), xs)
+        _dll.openmc_nuclide_collapse_rate(self._index, MT, energy, flux, len(flux), xs)
         return xs.value
 
 
diff --git a/src/nuclide.cpp b/src/nuclide.cpp
index d6da7d60f..f4deeaf67 100644
--- a/src/nuclide.cpp
+++ b/src/nuclide.cpp
@@ -908,7 +908,7 @@ void Nuclide::calculate_urr_xs(int i_temp, Particle& p) const
 
 }
 
-double Nuclide::one_group_xs(int MT, gsl::span<const double> energy, gsl::span<const double> flux) const
+double Nuclide::collapse_rate(int MT, gsl::span<const double> energy, gsl::span<const double> flux) const
 {
   Expects(MT > 0);
   Expects(energy.size() > 0);
@@ -919,7 +919,7 @@ double Nuclide::one_group_xs(int MT, gsl::span<const double> energy, gsl::span<c
 
   const auto& rx = reactions_[i_rx];
   const auto& grid = grid_[0].energy;
-  return rx->one_group_xs(energy, flux, grid);
+  return rx->collapse_rate(energy, flux, grid);
 }
 
 //==============================================================================
@@ -1044,14 +1044,14 @@ openmc_nuclide_name(int index, const char** name)
 }
 
 extern "C" int
-openmc_nuclide_one_group_xs(int index, int MT, const double* energy, const double* flux, int n, double* xs)
+openmc_nuclide_collapse_rate(int index, int MT, const double* energy, const double* flux, int n, double* xs)
 {
   if (index < 0 || index >= data::nuclides.size()) {
     set_errmsg("Index in nuclides vector is out of bounds.");
     return OPENMC_E_OUT_OF_BOUNDS;
   }
 
-  *xs = data::nuclides[index]->one_group_xs(MT, {energy, energy + n + 1}, {flux, flux + n});
+  *xs = data::nuclides[index]->collapse_rate(MT, {energy, energy + n + 1}, {flux, flux + n});
   return 0;
 }
 
diff --git a/src/reaction.cpp b/src/reaction.cpp
index 2f53af56a..fbe9dec1a 100644
--- a/src/reaction.cpp
+++ b/src/reaction.cpp
@@ -85,7 +85,7 @@ Reaction::Reaction(hid_t group, const std::vector<int>& temperatures)
 }
 
 double
-Reaction::one_group_xs(gsl::span<const double> energy, gsl::span<const double> flux, const std::vector<double>& grid) const
+Reaction::collapse_rate(gsl::span<const double> energy, gsl::span<const double> flux, const std::vector<double>& grid) const
 {
   // TODO: Figure out how to deal with temperature
   int i_temp = 0;