Update docs/index.rst

rabernat · joshmoore · web-flow · commit e01eca8c9410 · 2020-05-07T08:40:20.000-04:00
Co-authored-by: Josh Moore &lt;j.a.moore@dundee.ac.uk&gt;
diff --git a/docs/index.rst b/docs/index.rst
@@ -4,7 +4,7 @@
 Zarr
 ====
 
-Zarr is format for the storage of chunked, compressed, N-dimensional arrays.
+Zarr is a format for the storage of chunked, compressed, N-dimensional arrays.
 These documents describe the Zarr format and its Python implementation.
 
 Highlights
