diff --git a/source/faq/storage.txt b/source/faq/storage.txt
index dafbd8e417d..897b17a12ea 100644
--- a/source/faq/storage.txt
+++ b/source/faq/storage.txt
@@ -18,12 +18,13 @@ the :doc:`complete list of FAQs </faq>` or post your question to the
 What are memory mapped files?
 -----------------------------
 
-Memory mapped files are a way of keeping files and data
-up to date in memory using the system call ``mmap()``. MongoDB uses
-memory mapped files as its storage engine. By using memory mapped
-files MongoDB can treat the content of its data files as if they were
-in memory. This provides MongoDB with an extremely fast and simple
-method for accessing and manipulating data.
+
+A memory-mapped file is a file whose data has been mapped to a region of
+virtual memory via the ``mmap()`` system call. Memory-mapped files play a
+critical role in the MongoDB storage engine. By using memory mapped files
+MongoDB can treat the content of its data files as if they were in memory.
+This provides MongoDB with an extremely fast and simple method for accessing
+and manipulating data.
 
 How do memory mapped files work?
 --------------------------------