diff --git a/doc/concepts/index-diag-2.html b/doc/concepts/index-diag-2.html
index 0d5ff035ba..633cd39a00 100644
--- a/doc/concepts/index-diag-2.html
+++ b/doc/concepts/index-diag-2.html
@@ -36,7 +36,7 @@
 </div>
 <div class="diag-caption">
   The recipe is the core abstraction to building networks. It declares a number
-  of cells present in the network and will then be interrogate for each about
+  of cells present in the network and will then be interrogated for each about
   its properties. By asking the recipe about each cell in isolation, Arbor can
   build the network in parallel while keeping memory consumption low.
 </div>