diff --git a/src/INSTALL b/src/INSTALL
index bd6ff77c..cdcbe049 100644
--- a/src/INSTALL
+++ b/src/INSTALL
@@ -331,7 +331,7 @@ Chapter 5. Installation and configuration
 
    Recoll indexing options are set inside text configuration files located in
    a configuration directory. There can be several such directories, each of
-   which define the parameters for one index.
+   which defines the parameters for one index.
 
    The configuration files can be edited by hand or through the Index
    configuration dialog (Preferences menu). The GUI tool will try to respect
diff --git a/src/README b/src/README
index 6b56a10d..3173346d 100644
--- a/src/README
+++ b/src/README
@@ -3240,7 +3240,7 @@ Chapter 5. Installation and configuration
 
    Recoll indexing options are set inside text configuration files located in
    a configuration directory. There can be several such directories, each of
-   which define the parameters for one index.
+   which defines the parameters for one index.
 
    The configuration files can be edited by hand or through the Index
    configuration dialog (Preferences menu). The GUI tool will try to respect