diff --git a/pint/default_en.txt b/pint/default_en.txt
index d89bca566..b32908731 100644
--- a/pint/default_en.txt
+++ b/pint/default_en.txt
@@ -233,9 +233,9 @@ rads = 1e-2 * gray
 roentgen = 2.58e-4 * coulomb / kilogram
 
 # Temperature
-degC = kelvin; offset: 273.15 = °C = degree_Celsius = celsius
-degR = 5 / 9 * kelvin; offset: 0 = °R = degree_Rankine = rankine
-degF = 5 / 9 * kelvin; offset: 255.372222 = °F = degree_Fahrenheit = fahrenheit
+degree_Celsius = kelvin; offset: 273.15 = °C = degC = celsius
+degree_Rankine = 5 / 9 * kelvin; offset: 0 = °R = degR = rankine
+degree_Fahrenheit = 5 / 9 * kelvin; offset: 255.372222 = °F = degF = fahrenheit
 
 # Time
 minute = 60 * second = min
diff --git a/pint/registry.py b/pint/registry.py
index 6c9d953b8..0129ba5d5 100644
--- a/pint/registry.py
+++ b/pint/registry.py
@@ -279,7 +279,8 @@ def _define(self, definition):
             else:
                 d_symbol = None
 
-            d_aliases = tuple('Δ' + alias for alias in definition.aliases)
+            d_aliases = tuple('Δ' + alias for alias in definition.aliases) + \
+                        tuple('delta_' + alias for alias in definition.aliases)
 
             d_reference = UnitsContainer(dict((ref, value)
                                          for ref, value in definition.reference.items()))