diff --git a/lib/Alchemy/Phrasea/SearchEngine/Elastic/Exception/ThesaurusException.php b/lib/Alchemy/Phrasea/SearchEngine/Elastic/Exception/ThesaurusException.php
new file mode 100644
index 0000000000..bab7e3260a
--- /dev/null
+++ b/lib/Alchemy/Phrasea/SearchEngine/Elastic/Exception/ThesaurusException.php
@@ -0,0 +1,16 @@
+<?php
+
+/*
+ * This file is part of Phraseanet
+ *
+ * (c) 2005-2014 Alchemy
+ *
+ * For the full copyright and license information, please view the LICENSE
+ * file that was distributed with this source code.
+ */
+
+namespace Alchemy\Phrasea\SearchEngine\Elastic\Exception;
+
+class ThesaurusException extends Exception
+{
+}
diff --git a/lib/Alchemy/Phrasea/SearchEngine/Elastic/Indexer/TermIndexer.php b/lib/Alchemy/Phrasea/SearchEngine/Elastic/Indexer/TermIndexer.php
index a0acb12aa7..8e047187e6 100644
--- a/lib/Alchemy/Phrasea/SearchEngine/Elastic/Indexer/TermIndexer.php
+++ b/lib/Alchemy/Phrasea/SearchEngine/Elastic/Indexer/TermIndexer.php
@@ -14,6 +14,8 @@ namespace Alchemy\Phrasea\SearchEngine\Elastic\Indexer;
 use Alchemy\Phrasea\SearchEngine\Elastic\BulkOperation;
 use Alchemy\Phrasea\SearchEngine\Elastic\ElasticSearchEngine;
 use Alchemy\Phrasea\SearchEngine\Elastic\Mapping;
+use Alchemy\Phrasea\SearchEngine\Elastic\Thesaurus\Navigator;
+use Alchemy\Phrasea\SearchEngine\Elastic\Thesaurus\TermVisitor;
 use Closure;
 use Elasticsearch\Client;
 use databox;
@@ -31,20 +33,22 @@ class TermIndexer
 
     public function __construct(\appbox $appbox)
     {
-        //$this->document = self::thesaurusFromDatabox($databox);
         $this->appbox = $appbox;
     }
 
     public function populateIndex(BulkOperation $bulk)
     {
-        // Helper to fetch record related data
-        //$recordHelper = new RecordHelper($this->appbox);
+        // TODO Create object to query thesaurus for term paths/synonyms
+
+        $navigator = new Navigator();
 
         foreach ($this->appbox->get_databoxes() as $databox) {
-            // TODO Create object to query thesaurus for term paths/synonyms
-            // TODO Extract record indexing logic in a RecordIndexer class
-            //$fetcher = new RecordFetcher($databox, $recordHelper);
-            //$fetcher->setBatchSize(200);
+            $document = self::thesaurusFromDatabox($databox);
+            $visitor = new TermVisitor(function ($term) use ($bulk) {
+                printf("- %s (%s)\n", $term['path'], $term['value']);
+            });
+            $navigator->walk($document, $visitor);
+
             while ($record = false) {
                 $params = array();
                 $params['id'] = $record['id'];
diff --git a/lib/Alchemy/Phrasea/SearchEngine/Elastic/Thesaurus/Navigator.php b/lib/Alchemy/Phrasea/SearchEngine/Elastic/Thesaurus/Navigator.php
new file mode 100644
index 0000000000..0756a51e90
--- /dev/null
+++ b/lib/Alchemy/Phrasea/SearchEngine/Elastic/Thesaurus/Navigator.php
@@ -0,0 +1,57 @@
+<?php
+
+/*
+ * This file is part of Phraseanet
+ *
+ * (c) 2005-2014 Alchemy
+ *
+ * For the full copyright and license information, please view the LICENSE
+ * file that was distributed with this source code.
+ */
+
+namespace Alchemy\Phrasea\SearchEngine\Elastic\Thesaurus;
+
+use Alchemy\Phrasea\SearchEngine\Elastic\BulkOperation;
+use Alchemy\Phrasea\SearchEngine\Elastic\ElasticSearchEngine;
+use Alchemy\Phrasea\SearchEngine\Elastic\Mapping;
+use Closure;
+use Elasticsearch\Client;
+use databox;
+
+use DOMDocument;
+use DOMElement;
+use DOMNode;
+
+class Navigator
+{
+    const THESAURUS_TAG_NAME = 'thesaurus';
+    const CONCEPT_TAG_NAME = 'te';
+    const TERM_TAG_NAME = 'sy';
+
+    public function walk(DOMNode $node, VisitorInterface $visitor)
+    {
+        if ($this->isConcept($node)) {
+            $visitor->visitConcept($node);
+            foreach ($node->childNodes as $child) {
+                $this->walk($child, $visitor);
+            }
+            $visitor->leaveConcept($node);
+        } elseif ($this->isTerm($node)) {
+            $visitor->visitTerm($node);
+        } else {
+            foreach ($node->childNodes as $child) {
+                $this->walk($child, $visitor);
+            }
+        }
+    }
+
+    private function isConcept(DOMNode $node)
+    {
+        return $node instanceof DOMElement && $node->tagName === self::CONCEPT_TAG_NAME;
+    }
+
+    private function isTerm(DOMNode $node)
+    {
+        return $node instanceof DOMElement && $node->tagName === self::TERM_TAG_NAME;
+    }
+}
diff --git a/lib/Alchemy/Phrasea/SearchEngine/Elastic/Thesaurus/TermVisitor.php b/lib/Alchemy/Phrasea/SearchEngine/Elastic/Thesaurus/TermVisitor.php
new file mode 100644
index 0000000000..489147a893
--- /dev/null
+++ b/lib/Alchemy/Phrasea/SearchEngine/Elastic/Thesaurus/TermVisitor.php
@@ -0,0 +1,145 @@
+<?php
+
+/*
+ * This file is part of Phraseanet
+ *
+ * (c) 2005-2014 Alchemy
+ *
+ * For the full copyright and license information, please view the LICENSE
+ * file that was distributed with this source code.
+ */
+
+namespace Alchemy\Phrasea\SearchEngine\Elastic\Thesaurus;
+
+use Alchemy\Phrasea\SearchEngine\Elastic\BulkOperation;
+use Alchemy\Phrasea\SearchEngine\Elastic\StringUtils;
+use Alchemy\Phrasea\SearchEngine\Elastic\Exception\ThesaurusException;
+use Closure;
+use Elasticsearch\Client;
+use DOMDocument;
+use DOMNodeList;
+use DOMElement;
+use DOMNode;
+
+class TermVisitor implements VisitorInterface
+{
+    const TERM_TAG_NAME = 'sy';
+    const TERM_LANG_ATTR = 'lng';
+    const TERM_VALUE_ATTR = 'v';
+    // So, this is a huuuge regex to match a group of words eventually followed
+    // by another group of words in parenthesis. It also takes care of trimming
+    // spaces.
+    const TERM_REGEX = '/^\s*(\w[^\(\)]*\w|\w)\s*(?:\(\s*([^\(\)]*[^\s\(\)])\s*\))?/u';
+    //                       [_____term______]       (   [_____context_____]    )
+
+    const PATH_LANG = 'en';
+
+    private $path = [];
+    private $termCallback;
+
+    public function __construct(Closure $termCallback)
+    {
+        $this->termCallback = $termCallback;
+    }
+
+    public function visitConcept(DOMElement $element)
+    {
+        array_push($this->path, $this->getConceptPathSegment($element));
+    }
+
+    public function visitTerm(DOMElement $element)
+    {
+        $value = $this->getTermValue($element);
+
+        $term = $this->parseTermValue($value);
+        $term += [
+            'path' => $this->getCurrentPathAsString(),
+            'lang' => $this->getTermAttribute($element, self::TERM_LANG_ATTR)
+        ];
+
+        call_user_func($this->termCallback, $term);
+    }
+
+    public function leaveConcept(DOMElement $element)
+    {
+        array_pop($this->path);
+    }
+
+    private function parseTermValue($value)
+    {
+        preg_match(self::TERM_REGEX, $value, $matches);
+
+        return [
+            'raw_value' => $value,
+            'value'     => isset($matches[1]) ? $matches[1] : null,
+            'context'   => isset($matches[2]) ? $matches[2] : null
+        ];
+    }
+
+    private function getCurrentPathAsString()
+    {
+        return sprintf('/%s', implode('/', $this->path));
+    }
+
+    private function getConceptPathSegment(DOMElement $element)
+    {
+        // Path segment is named according to the first english term, and
+        // default to the first term.
+        $terms = $this->filter($element->childNodes, array($this, 'isTerm'));
+        $term = $this->find($terms, array($this, 'isPathLang'));
+        if (!$term) {
+            if (isset($terms[0])) {
+                $term = $terms[0];
+            } else {
+                throw new ThesaurusException(sprintf('No term linked to concept at path "%s".', $element->getNodePath()));
+            }
+        }
+
+        return StringUtils::slugify($this->getTermValue($term));
+    }
+
+    private function isTerm(DOMNode $node)
+    {
+        return $node instanceof DOMElement && $node->tagName === self::TERM_TAG_NAME;
+    }
+
+    private function isPathLang(DOMElement $element)
+    {
+        return $element->getAttribute(self::TERM_LANG_ATTR) === self::PATH_LANG;
+    }
+
+    private function getTermValue(DOMElement $term)
+    {
+        return $this->getTermAttribute($term, self::TERM_VALUE_ATTR);
+    }
+
+    private function getTermAttribute(DOMElement $term, $attribute)
+    {
+        if ($term->hasAttribute($attribute)) {
+            return $term->getAttribute($attribute);
+        }
+    }
+
+    // DOM Helpers
+
+    private function filter(DOMNodeList $list, Callable $callback)
+    {
+        $filtered = [];
+        foreach ($list as $node) {
+            if (call_user_func($callback, $node)) {
+                $filtered[] = $node;
+            }
+        }
+
+        return $filtered;
+    }
+
+    private function find(array $list, Callable $callback)
+    {
+        foreach ($list as $node) {
+            if (call_user_func($callback, $node)) {
+                return $node;
+            }
+        }
+    }
+}
diff --git a/lib/Alchemy/Phrasea/SearchEngine/Elastic/Thesaurus/VisitorInterface.php b/lib/Alchemy/Phrasea/SearchEngine/Elastic/Thesaurus/VisitorInterface.php
new file mode 100644
index 0000000000..9d463df6aa
--- /dev/null
+++ b/lib/Alchemy/Phrasea/SearchEngine/Elastic/Thesaurus/VisitorInterface.php
@@ -0,0 +1,21 @@
+<?php
+
+/*
+ * This file is part of Phraseanet
+ *
+ * (c) 2005-2014 Alchemy
+ *
+ * For the full copyright and license information, please view the LICENSE
+ * file that was distributed with this source code.
+ */
+
+namespace Alchemy\Phrasea\SearchEngine\Elastic\Thesaurus;
+
+use DOMElement;
+
+interface VisitorInterface
+{
+    public function visitConcept(DOMElement $element);
+    public function visitTerm(DOMElement $element);
+    public function leaveConcept(DOMElement $element);
+}