title: WP_Query tax_query multiple taxonomies and terms
body: <p>I'm having a bit of trouble returning posts with multiple taxonomies and terms. Hoping someone with far more knowledge than myself can help me understand.</p>
  
  <p>I'm using a select menu to populate the select options with taxonomy information of a page (in this case, the Products page). All is good with a single taxonomy and term in the tax_query but as soon as I try to use an array to pass multiples, i'm no longer returning anything. This seems simple enough but I'm missing something. Any ideas?</p>
  
  <p>Here is what I'm working with:</p>
  
  <pre><code>$producttype = $_GET['ProductType'];
  $businessunit = $_GET['BusinessUnit'];
  $products = new WP_Query( array( 
    'post_type' =&gt; 'products',
    'posts_per_page' =&gt; 15,
    'orderby' =&gt; 'title',
    'order'   =&gt; 'ASC',
    'paged' =&gt; $paged,
    'tax_query' =&gt; array(
      'relation' =&gt; 'OR',
       array(
         'taxonomy' =&gt; 'producttype',
         'field' =&gt; 'name',
         'term' =&gt; $producttype
       ),
       array(
         'taxonomy' =&gt; 'businessunit',
         'field' =&gt; 'name',
         'term' =&gt; $businessunit
       )
    )
  )
  </code></pre>