Is it possible to remove the contextual link for deleting a node? In Drupal 7, can I somehow remove the "delete"-link from the contextual menu? 

Some users don't realize that this actually deletes the node. They think it only removes it from the current page but still exists in the database.
You can implement hook_menu_contextual_links_alter() to remove the "delete" link from the contextual links. 

function YOURMODULE_menu_contextual_links_alter(&amp;$links, $router_item, $root_path){
  unset($links['node-delete']);
}


However, if your users are irresponsible enough to believe that "deleting" a node does not actually delete it, you may be better off simply removing those users' permissions to delete nodes at all.