base directories / URL

Is there a way to handle base directories for taxonomies that result in a 404. For example my URLs are:

http://skipology.com/category/…
http://skipology.com/app/…

but the taxonomies / base directories above result in 404. Can they be redirected to a taxonomy index page (which I may need to create) for example without impacting the child directory (post) or is there a better option. If so how? I suspect the answer lies in redirects but I’m not confident.

You can manually create pages named category and app in admin under the Pages menu, and use a custom page template for each to list out taxonomy terms or whatever you need.

EDIT – 301 redirect a request that matches the pagename rewrite to another page:

function wpa_parse_query( $query ){
    if( isset( $query->query_vars['pagename'] )
        && 'apps' == $query->query_vars['pagename'] ){
            wp_redirect( home_url( '/other-page/' ), 301 );
            exit;
    }
}
add_action( 'parse_query', 'wpa_parse_query' );