From 4cf4e8bc0c0d737eba468497e74583529e634937 Mon Sep 17 00:00:00 2001
From: Thiago Carvalho <thiago.carvalho@westwing.de>
Date: Sun, 15 Feb 2015 19:37:49 +0100
Subject: [PATCH 1/2] glossary

---
 src/doc/trpl/SUMMARY.md  |  1 +
 src/doc/trpl/glossary.md | 17 +++++++++++++++++
 2 files changed, 18 insertions(+)
 create mode 100644 src/doc/trpl/glossary.md

diff --git a/src/doc/trpl/SUMMARY.md b/src/doc/trpl/SUMMARY.md
index 9d65f30e72379..f2eadc3c33e37 100644
--- a/src/doc/trpl/SUMMARY.md
+++ b/src/doc/trpl/SUMMARY.md
@@ -36,3 +36,4 @@
     * [Macros](macros.md)
     * [Compiler Plugins](plugins.md)
 * [Conclusion](conclusion.md)
+* [Glossary](glossary.md)
diff --git a/src/doc/trpl/glossary.md b/src/doc/trpl/glossary.md
new file mode 100644
index 0000000000000..a8d447386b7dd
--- /dev/null
+++ b/src/doc/trpl/glossary.md
@@ -0,0 +1,17 @@
+% Glossary
+
+In this section we briefly explain terms that you may not be familiar with.
+
+This book avoids, as much as possible, overcomplicated terms. Nevertheless, the following were deemed important enough that omitting them would be a disservice to the reader.
+
+### Arity
+
+Arity refers to the number of arguments a function or operation takes.
+
+```rust
+let x = (2, 3);
+let y = (4, 6);
+let z = (8, 2, 6);
+```
+
+In the example above `x` and `y` have arity 2. `z` has arity 3.

From 9783cc282204b4f72c1300f5acd40926925bd53e Mon Sep 17 00:00:00 2001
From: Thiago Carvalho <thiago.carvalho@westwing.de>
Date: Sun, 15 Feb 2015 20:41:44 +0100
Subject: [PATCH 2/2] improve text

---
 src/doc/trpl/glossary.md | 5 ++---
 1 file changed, 2 insertions(+), 3 deletions(-)

diff --git a/src/doc/trpl/glossary.md b/src/doc/trpl/glossary.md
index a8d447386b7dd..156f33748673b 100644
--- a/src/doc/trpl/glossary.md
+++ b/src/doc/trpl/glossary.md
@@ -1,8 +1,7 @@
 % Glossary
 
-In this section we briefly explain terms that you may not be familiar with.
-
-This book avoids, as much as possible, overcomplicated terms. Nevertheless, the following were deemed important enough that omitting them would be a disservice to the reader.
+Not every Rustacean has a background in systems programming, nor in computer
+science, so we've added explanations of terms that might be unfamiliar.
 
 ### Arity