How to get taxonomy term by description, programatically
Using the EntityFieldQuery (this is untested)

  $query = new EntityFieldQuery();
  $query-&gt;entityCondition('entity_type', 'taxonomy_term')
    -&gt;entityCondition('bundle', array('my_vocabulary'))
    -&gt;propertyCondition('description', 'my_term_description');
  $result = $query-&gt;execute();
  $tids = array_keys($result['taxonomy_term']);

  return $tids;


More information https://www.drupal.org/docs/7/creating-custom-modules/howtos/how-to-use-entityfieldquery-for-drupal-7