diff -r a91f0d4a2381 Doc/library/cmath.rst
--- a/Doc/library/cmath.rst	Wed Jul 02 08:37:22 2014 +0300
+++ b/Doc/library/cmath.rst	Wed Jul 02 08:46:20 2014 +0100
@@ -149,13 +149,13 @@
 
 .. function:: acosh(x)
 
-   Return the hyperbolic arc cosine of *x*. There is one branch cut, extending left
-   from 1 along the real axis to -∞, continuous from above.
+   Return the inverse hyperbolic cosine of *x*. There is one branch cut,
+   extending left from 1 along the real axis to -∞, continuous from above.
 
 
 .. function:: asinh(x)
 
-   Return the hyperbolic arc sine of *x*. There are two branch cuts:
+   Return the inverse hyperbolic sine of *x*. There are two branch cuts:
    One extends from ``1j`` along the imaginary axis to ``∞j``,
    continuous from the right.  The other extends from ``-1j`` along
    the imaginary axis to ``-∞j``, continuous from the left.
@@ -163,7 +163,7 @@
 
 .. function:: atanh(x)
 
-   Return the hyperbolic arc tangent of *x*. There are two branch cuts: One
+   Return the inverse hyperbolic tangent of *x*. There are two branch cuts: One
    extends from ``1`` along the real axis to ``∞``, continuous from below. The
    other extends from ``-1`` along the real axis to ``-∞``, continuous from
    above.
diff -r a91f0d4a2381 Modules/cmathmodule.c
--- a/Modules/cmathmodule.c	Wed Jul 02 08:37:22 2014 +0300
+++ b/Modules/cmathmodule.c	Wed Jul 02 08:46:20 2014 +0100
@@ -192,7 +192,7 @@
 PyDoc_STRVAR(c_acosh_doc,
 "acosh(x)\n"
 "\n"
-"Return the hyperbolic arccosine of x.");
+"Return the inverse hyperbolic cosine of x.");
 
 
 static Py_complex
@@ -249,7 +249,7 @@
 PyDoc_STRVAR(c_asinh_doc,
 "asinh(x)\n"
 "\n"
-"Return the hyperbolic arc sine of x.");
+"Return the inverse hyperbolic sine of x.");
 
 
 static Py_complex
@@ -353,7 +353,7 @@
 PyDoc_STRVAR(c_atanh_doc,
 "atanh(x)\n"
 "\n"
-"Return the hyperbolic arc tangent of x.");
+"Return the inverse hyperbolic tangent of x.");
 
 
 static Py_complex
diff -r a91f0d4a2381 Modules/mathmodule.c
--- a/Modules/mathmodule.c	Wed Jul 02 08:37:22 2014 +0300
+++ b/Modules/mathmodule.c	Wed Jul 02 08:46:20 2014 +0100
@@ -873,18 +873,18 @@
 FUNC1(acos, acos, 0,
       "acos(x)\n\nReturn the arc cosine (measured in radians) of x.")
 FUNC1(acosh, m_acosh, 0,
-      "acosh(x)\n\nReturn the hyperbolic arc cosine (measured in radians) of x.")
+      "acosh(x)\n\nReturn the inverse hyperbolic cosine of x.")
 FUNC1(asin, asin, 0,
       "asin(x)\n\nReturn the arc sine (measured in radians) of x.")
 FUNC1(asinh, m_asinh, 0,
-      "asinh(x)\n\nReturn the hyperbolic arc sine (measured in radians) of x.")
+      "asinh(x)\n\nReturn the inverse hyperbolic sine of x.")
 FUNC1(atan, atan, 0,
       "atan(x)\n\nReturn the arc tangent (measured in radians) of x.")
 FUNC2(atan2, m_atan2,
       "atan2(y, x)\n\nReturn the arc tangent (measured in radians) of y/x.\n"
       "Unlike atan(y/x), the signs of both x and y are considered.")
 FUNC1(atanh, m_atanh, 0,
-      "atanh(x)\n\nReturn the hyperbolic arc tangent (measured in radians) of x.")
+      "atanh(x)\n\nReturn the inverse hyperbolic tangent of x.")
 
 static PyObject * math_ceil(PyObject *self, PyObject *number) {
     _Py_IDENTIFIER(__ceil__);