WordPress query with items from more than one selfdefined taxonomy as `term` argument

I managed to do it. I used the following query parameter:

'tax_query' => array(
array('taxonomy' => 'wpccategories',
'field' => 'slug',
'terms' => $termz
)
)

With $termz being: $termz = wp_get_object_terms($id, 'wpccategories', array("fields" => "slugs"));

The problem I struggled with was that I needed to use singular 'field'with singular 'slug' in the tax_query (I knew this) but I needed to use plurar in the wp_get_object_terms function. So the other way around of any other kind doesn’t seem to work.