diff --git a/doc/api.rst b/doc/api.rst
index e191304e95c..4492d882355 100644
--- a/doc/api.rst
+++ b/doc/api.rst
@@ -414,7 +414,7 @@ Universal functions
    for the ``xarray.ufuncs`` module, which should not be used for new code
    unless compatibility with versions of NumPy prior to v1.13 is required.
 
-This functions are copied from NumPy, but extended to work on NumPy arrays,
+These functions are copied from NumPy, but extended to work on NumPy arrays,
 dask arrays and all xarray objects. You can find them in the ``xarray.ufuncs``
 module: