diff --git a/rend-spec.txt b/rend-spec.txt
index aef21ad..ceb41b6 100644
--- a/rend-spec.txt
+++ b/rend-spec.txt
@@ -32,8 +32,8 @@ $Id$
 
 0.1. Notation, conventions and prerequisites
 
-   In the specifications below, we use the same notation as in
-   "tor-spec.txt".  The service specified here also requires the
+   In the specifications below, we use the same notation and terminology
+   as in "tor-spec.txt".  The service specified here also requires the
    existence of an onion routing network as specified in that file.
 
         H(x) is a SHA1 digest of x.
@@ -48,6 +48,15 @@ $Id$
    location-hidden service, and "Bob" will refer to a user running a
    location-hidden service.
 
+   An OP is (as defined elsewhere) an "Onion Proxy" or Tor client.
+
+   An OR is (as defined elsewhere) an "Onion Router" or Tor server.
+
+   An "Introduction point" is a Tor server chosen to be Bob's medium-term
+   'meeting place'.  A "Rendezvous point" is a Tor server chosen by Alice to
+   be a short-term communication relay between her and Bob.  All Tor servers
+   potentially act as introduction and rendezvous points.
+
 0.2. Protocol outline
 
    1. Bob->Bob's OP: "Offer IP:Port as
diff --git a/tor-spec.txt b/tor-spec.txt
index 4c9d16d..55e3ce0 100644
--- a/tor-spec.txt
+++ b/tor-spec.txt
@@ -552,6 +552,8 @@ see tor-design.pdf.
         12 -- RELAY_RESOLVED  [backward]
         13 -- RELAY_BEGIN_DIR [forward]
 
+        32..40 -- Used for hidden services; see rend-spec.txt.
+
    Commands labelled as "forward" must only be sent by the originator
    of the circuit. Commands labelled as "backward" must only be sent by
    other nodes in the circuit back to the originator. Commands marked