diff --git a/Doc/library/errno.rst b/Doc/library/errno.rst
index 5122c69697ef91..67b3b9da4af127 100644
--- a/Doc/library/errno.rst
+++ b/Doc/library/errno.rst
@@ -652,6 +652,7 @@ defined by the module.  The specific list of defined symbols is available as
 
    Quota exceeded
 
+
 .. data:: EQFULL
 
    Interface output queue is full
@@ -666,3 +667,234 @@ defined by the module.  The specific list of defined symbols is available as
    .. availability:: WASI, FreeBSD
 
    .. versionadded:: 3.11.1
+
+
+.. data:: ENOMEDIUM
+
+   No medium found
+
+
+.. data:: EMEDIUMTYPE
+
+   Wrong medium type
+
+
+.. data:: ECANCELED
+
+   Operation Canceled
+
+
+.. data:: ENOKEY
+
+   Required key not available
+
+
+.. data:: EKEYEXPIRED
+
+   Key has expired
+
+
+.. data:: EKEYREVOKED
+
+   Key has been revoked
+
+
+.. data:: EKEYREJECTED
+
+   Key was rejected by service
+
+
+.. data:: EOWNERDEAD
+
+   Owner died
+
+
+.. data:: ENOTRECOVERABLE
+
+   State not recoverable
+
+
+.. data:: ERFKILL
+
+   Operation not possible due to RF-kill
+
+
+.. data:: EHWPOISON
+
+   Memory page has hardware error
+
+
+.. data:: ENOTSUP
+
+   Operation not supported
+
+   .. availability:: Unix.
+
+
+.. data:: ELOCKUNMAPPED
+
+   Locked lock was unmapped
+
+   .. availability:: Unix.
+
+
+.. data:: ENOTACTIVE
+
+   Facility is not active
+
+   .. availability:: Unix.
+
+
+.. data:: EAUTH
+
+   Authentication error
+
+   .. availability:: OSX.
+
+
+.. data:: EBADARCH
+
+   Bad CPU type in executable
+
+   .. availability:: OSX.
+
+
+.. data:: EBADEXEC
+
+   Bad executable (or shared library)
+
+   .. availability:: OSX.
+
+
+.. data:: EBADMACHO
+
+   Malformed Mach-o file
+
+   .. availability:: OSX.
+
+
+.. data:: EBADRPC
+
+   RPC struct is bad
+
+   .. availability:: OSX.
+
+
+.. data:: EDEVERR
+
+   Device error
+
+   .. availability:: OSX.
+
+
+.. data:: EFTYPE
+
+   Inappropriate file type or format
+
+   .. availability:: OSX.
+
+
+.. data:: ENEEDAUTH
+
+   Need authenticator
+
+   .. availability:: OSX.
+
+
+.. data:: ENEEDAUTH
+
+   Need authenticator
+
+   .. availability:: OSX.
+
+
+.. data:: ENOATTR
+
+   Attribute not found
+
+   .. availability:: OSX.
+
+
+.. data:: ENOPOLICY
+
+   Policy not found
+
+   .. availability:: OSX.
+
+
+.. data:: EPROCLIM
+
+   Too many processes
+
+   .. availability:: OSX.
+
+
+.. data:: EPROCUNAVAIL
+
+   Bad procedure for program
+
+   .. availability:: OSX.
+
+
+.. data:: EPROGMISMATCH
+
+   Program version wrong
+
+   .. availability:: OSX.
+
+
+.. data:: EPROGUNAVAIL
+
+   RPC prog. not avail
+
+   .. availability:: OSX.
+
+
+.. data:: EPWROFF
+
+   Device power is off
+
+   .. availability:: OSX.
+
+
+.. data:: ERPCMISMATCH
+
+   RPC version wrong
+
+   .. availability:: OSX.
+
+
+.. data:: ESHLIBVERS
+
+   Shared library version mismatch
+
+   .. availability:: OSX.
+
+
+.. data:: WSASYSNOTREADY
+
+   Network subsystem is unavailable.
+
+   .. availability:: Windows.
+
+
+.. data:: WSANOTINITIALISED
+
+   Successful WSAStartup not yet performed.
+
+   .. availability:: Windows.
+
+
+.. data:: WSAEDISCON
+
+   Graceful shutdown in progress.
+
+   .. availability:: Windows.
+
+
+.. data:: WSAVERNOTSUPPORTED
+
+   Winsock.dll version out of range.
+
+   .. availability:: Windows.
+
diff --git a/Misc/NEWS.d/next/Documentation/2020-06-05-17-05-00.bpo-40869.YErrno.rst b/Misc/NEWS.d/next/Documentation/2020-06-05-17-05-00.bpo-40869.YErrno.rst
new file mode 100644
index 00000000000000..890dd3a481f64f
--- /dev/null
+++ b/Misc/NEWS.d/next/Documentation/2020-06-05-17-05-00.bpo-40869.YErrno.rst
@@ -0,0 +1 @@
+Added :data:`errno.EHWPOISON` descriptions into :mod:`errno`
diff --git a/Modules/errnomodule.c b/Modules/errnomodule.c
index fddde960a5fe9a..f0c34f0929150a 100644
--- a/Modules/errnomodule.c
+++ b/Modules/errnomodule.c
@@ -614,7 +614,7 @@ errno_exec(PyObject *module)
     add_errcode("EBFONT", EBFONT, "Bad font file format");
 #endif
 #ifdef EDEADLOCK
-    add_errcode("EDEADLOCK", EDEADLOCK, "Error EDEADLOCK");
+    add_errcode("EDEADLOCK", EDEADLOCK, "File locking deadlock error");
 #endif
 #ifdef ETOOMANYREFS
     add_errcode("ETOOMANYREFS", ETOOMANYREFS, "Too many references: cannot splice");
@@ -671,19 +671,19 @@ errno_exec(PyObject *module)
     add_errcode("WSAESTALE", WSAESTALE, "Stale NFS file handle");
 #endif
 #ifdef WSAVERNOTSUPPORTED
-    add_errcode("WSAVERNOTSUPPORTED", WSAVERNOTSUPPORTED, "Error WSAVERNOTSUPPORTED");
+    add_errcode("WSAVERNOTSUPPORTED", WSAVERNOTSUPPORTED, "Winsock.dll version out of range.");
 #endif
 #ifdef WSAENETUNREACH
     add_errcode("WSAENETUNREACH", WSAENETUNREACH, "Network is unreachable");
 #endif
 #ifdef WSAEPROCLIM
-    add_errcode("WSAEPROCLIM", WSAEPROCLIM, "Error WSAEPROCLIM");
+    add_errcode("WSAEPROCLIM", WSAEPROCLIM, "Too many processes.");
 #endif
 #ifdef WSAEFAULT
     add_errcode("WSAEFAULT", WSAEFAULT, "Bad address");
 #endif
 #ifdef WSANOTINITIALISED
-    add_errcode("WSANOTINITIALISED", WSANOTINITIALISED, "Error WSANOTINITIALISED");
+    add_errcode("WSANOTINITIALISED", WSANOTINITIALISED, "Successful WSAStartup not yet performed.");
 #endif
 #ifdef WSAEUSERS
     add_errcode("WSAEUSERS", WSAEUSERS, "Too many users");
@@ -743,7 +743,7 @@ errno_exec(PyObject *module)
     add_errcode("WSAENOBUFS", WSAENOBUFS, "No buffer space available");
 #endif
 #ifdef WSAEDISCON
-    add_errcode("WSAEDISCON", WSAEDISCON, "Error WSAEDISCON");
+    add_errcode("WSAEDISCON", WSAEDISCON, "Graceful shutdown in progress.");
 #endif
 #ifdef WSAEINTR
     add_errcode("WSAEINTR", WSAEINTR, "Interrupted system call");
@@ -767,7 +767,7 @@ errno_exec(PyObject *module)
     add_errcode("WSAEPROTONOSUPPORT", WSAEPROTONOSUPPORT, "Protocol not supported");
 #endif
 #ifdef WSASYSNOTREADY
-    add_errcode("WSASYSNOTREADY", WSASYSNOTREADY, "Error WSASYSNOTREADY");
+    add_errcode("WSASYSNOTREADY", WSASYSNOTREADY, "Network subsystem is unavailable.");
 #endif
 #ifdef WSAEWOULDBLOCK
     add_errcode("WSAEWOULDBLOCK", WSAEWOULDBLOCK, "Operation would block");
@@ -853,6 +853,10 @@ errno_exec(PyObject *module)
 #ifdef ERFKILL
     add_errcode("ERFKILL", ERFKILL, "Operation not possible due to RF-kill");
 #endif
+#ifdef EHWPOISON
+    add_errcode("EHWPOISON", EHWPOISON, "Memory page has hardware error");
+#endif
+
 
     /* Solaris-specific errnos */
 #ifdef ECANCELED