Be consistent in the use of read-only.
diff --git a/Doc/library/mmap.rst b/Doc/library/mmap.rst
index d2a6d1e..a9a4ad8 100644
--- a/Doc/library/mmap.rst
+++ b/Doc/library/mmap.rst
@@ -26,7 +26,7 @@
For both the Unix and Windows versions of the constructor, *access* may be
specified as an optional keyword parameter. *access* accepts one of three
values: :const:`ACCESS_READ`, :const:`ACCESS_WRITE`, or :const:`ACCESS_COPY`
-to specify readonly, write-through or copy-on-write memory respectively.
+to specify read-only, write-through or copy-on-write memory respectively.
*access* can be used on both Unix and Windows. If *access* is not specified,
Windows mmap returns a write-through mapping. The initial memory values for
all three access types are taken from the specified file. Assignment to an