correct typo

README

@@ -2,7 +2,7 @@ jquery.inputmask is a jquery plugin which create an input mask ;-)
 
 The plugin is based on the maskedinput plugin of Josh Bush (http://digitalbush.com/projects/masked-input-plugin), but has finer control over the 'mask-definitions' and is fully compatible with the ui-datepicker
 
-A definitions can have a cardinality and have multiple prevalidators.
+A definition can have a cardinality and have multiple prevalidators.
 
 Example of some new definitions: