diff --git a/src/common/crypto.c b/src/common/crypto.c
index 200c74a27c..bc1ca6945e 100644
--- a/src/common/crypto.c
+++ b/src/common/crypto.c
@@ -509,7 +509,7 @@ crypto_pk_write_public_key_to_string(crypto_pk_env_t *env, char **dest,
   tor_assert(buf->length >= 0);
   *dest = tor_malloc(buf->length+1);
   memcpy(*dest, buf->data, buf->length);
-  (*dest)[buf->length] = 0; /* null terminate it */
+  (*dest)[buf->length] = 0; /* nul terminate it */
   *len = buf->length;
   BUF_MEM_free(buf);
 
diff --git a/src/or/buffers.c b/src/or/buffers.c
index 86741e9733..69cfd30d36 100644
--- a/src/or/buffers.c
+++ b/src/or/buffers.c
@@ -878,14 +878,14 @@ fetch_from_buf_http(buf_t *buf,
   if (headers_out) {
     *headers_out = tor_malloc(headerlen+1);
     memcpy(*headers_out,buf->cur,headerlen);
-    (*headers_out)[headerlen] = 0; /* null terminate it */
+    (*headers_out)[headerlen] = 0; /* nul terminate it */
   }
   if (body_out) {
     tor_assert(body_used);
     *body_used = bodylen;
     *body_out = tor_malloc(bodylen+1);
     memcpy(*body_out,buf->cur+headerlen,bodylen);
-    (*body_out)[bodylen] = 0; /* null terminate it */
+    (*body_out)[bodylen] = 0; /* nul terminate it */
   }
   buf_remove_from_front(buf, headerlen+bodylen);
   return 1;
diff --git a/src/or/connection_edge.c b/src/or/connection_edge.c
index 508c2a65be..41948e055c 100644
--- a/src/or/connection_edge.c
+++ b/src/or/connection_edge.c
@@ -1919,14 +1919,14 @@ parse_extended_hostname(char *address)
     s = strrchr(address,'.');
     if (!s) return 0; /* no dot, thus normal */
     if (!strcmp(s+1,"exit")) {
-      *s = 0; /* null-terminate it */
+      *s = 0; /* nul-terminate it */
       return EXIT_HOSTNAME; /* .exit */
     }
     if (strcmp(s+1,"onion"))
       return NORMAL_HOSTNAME; /* neither .exit nor .onion, thus normal */
 
     /* so it is .onion */
-    *s = 0; /* null-terminate it */
+    *s = 0; /* nul-terminate it */
     if (strlcpy(query, address, REND_SERVICE_ID_LEN+1) >=
         REND_SERVICE_ID_LEN+1)
       goto failed;
diff --git a/src/or/control.c b/src/or/control.c
index 48139f3ce6..c2d86f8c7d 100644
--- a/src/or/control.c
+++ b/src/or/control.c
@@ -790,7 +790,7 @@ handle_control_getconf(connection_t *conn, uint32_t body_len, const char *body)
   int v0 = STATE_IS_V0(conn->state);
 
   questions = smartlist_create();
-  (void) body_len; /* body is null-terminated; so we can ignore len. */
+  (void) body_len; /* body is nul-terminated; so we can ignore len. */
   if (v0) {
     smartlist_split_string(questions, body, "\n",
                            SPLIT_SKIP_SPACE|SPLIT_IGNORE_BLANK, 0);
@@ -1160,7 +1160,7 @@ handle_control_mapaddress(connection_t *conn, uint32_t len, const char *body)
   char *r;
   size_t sz;
   int v0 = STATE_IS_V0(conn->state);
-  (void) len; /* body is null-terminated, so it's safe to ignore the length. */
+  (void) len; /* body is nul-terminated, so it's safe to ignore the length. */
 
   lines = smartlist_create();
   elts = smartlist_create();
@@ -1552,7 +1552,7 @@ handle_control_getinfo(connection_t *conn, uint32_t len, const char *body)
   char *msg = NULL, *ans = NULL;
   size_t msg_len;
   int v0 = STATE_IS_V0(conn->state);
-  (void) len; /* body is null-terminated, so it's safe to ignore the length. */
+  (void) len; /* body is nul-terminated, so it's safe to ignore the length. */
 
   questions = smartlist_create();
   if (v0)
@@ -1814,7 +1814,7 @@ handle_control_setpurpose(connection_t *conn, int for_circuits,
   routerinfo_t *ri = NULL;
   uint8_t new_purpose;
   smartlist_t *args = smartlist_create();
-  (void) len; /* body is null-terminated, so it's safe to ignore the length. */
+  (void) len; /* body is nul-terminated, so it's safe to ignore the length. */
   smartlist_split_string(args, body, " ",
                          SPLIT_SKIP_SPACE|SPLIT_IGNORE_BLANK, 0);
   if (smartlist_len(args)<2) {
diff --git a/src/or/directory.c b/src/or/directory.c
index fd787cc872..dd920893eb 100644
--- a/src/or/directory.c
+++ b/src/or/directory.c
@@ -590,7 +590,7 @@ directory_send_command(connection_t *conn, const char *platform,
  * "\%s [http[s]://]\%s HTTP/1..."
  * \endverbatim
  * If it's well-formed, strdup the second \%s into *<b>url</b>, and
- * null-terminate it. If the url doesn't start with "/tor/", rewrite it
+ * nul-terminate it. If the url doesn't start with "/tor/", rewrite it
  * so it does. Return 0.
  * Otherwise, return -1.
  */
diff --git a/src/or/dns.c b/src/or/dns.c
index 046bd5e6a5..fe02811695 100644
--- a/src/or/dns.c
+++ b/src/or/dns.c
@@ -941,7 +941,7 @@ dnsworker_main(void *data)
       crypto_thread_cleanup();
       spawn_exit();
     }
-    address[address_len] = 0; /* null terminate it */
+    address[address_len] = 0; /* nul terminate it */
 
     log_address = esc_for_log(safe_str(address));
     result = tor_lookup_hostname(address, &ip);
diff --git a/src/or/rendservice.c b/src/or/rendservice.c
index e6b2ca8cb4..ce3ca478c7 100644
--- a/src/or/rendservice.c
+++ b/src/or/rendservice.c
@@ -518,7 +518,7 @@ rend_service_introduce(circuit_t *circuit, const char *request,
     ptr=memchr(rp_nickname,0,nickname_field_len);
     if (!ptr || ptr == rp_nickname) {
       log_warn(LD_PROTOCOL,
-               "Couldn't find a null-padded nickname in INTRODUCE2 cell.");
+               "Couldn't find a nul-padded nickname in INTRODUCE2 cell.");
       return -1;
     }
     if ((version == 0 && !is_legal_nickname(rp_nickname)) ||