diff --git a/src/trie.c b/src/trie.c
index cd158724..9c7bf6b5 100644
--- a/src/trie.c
+++ b/src/trie.c
@@ -106,7 +106,7 @@ inline bool trie_node_is_free(trie_node_t node) {
 }
 
 inline trie_node_t trie_get_node(trie_t *self, uint32_t index) {
-    if ((index >= self->nodes->n) || index < ROOT_ID) return self->null_node;
+    if ((index >= self->nodes->n) || index < ROOT_NODE_ID) return self->null_node;
     return self->nodes->a[index];
 }
 
@@ -122,7 +122,7 @@ inline void trie_set_check(trie_t *self, uint32_t index, int32_t check) {
 
 
 inline trie_node_t trie_get_root(trie_t *self) {
-    return self->nodes->a[ROOT_ID];
+    return self->nodes->a[ROOT_NODE_ID];
 }
 
 inline trie_node_t trie_get_free_list(trie_t *self) {
@@ -233,7 +233,7 @@ static void trie_prune_up_to(trie_t *self, uint32_t p, uint32_t s) {
 }
 
 static void trie_prune(trie_t *self, uint32_t s) {
-    trie_prune_up_to(self, ROOT_ID, s);
+    trie_prune_up_to(self, ROOT_NODE_ID, s);
 }
 
 static void trie_get_transition_chars(trie_t *self, uint32_t node_id, unsigned char *transitions, uint32_t *num_transitions) {
@@ -621,8 +621,8 @@ bool trie_add_at_index(trie_t *self, uint32_t node_id, char *key, uint32_t data)
     unsigned char *ptr = (unsigned char *)key; 
     uint32_t last_node_id = node_id;
     trie_node_t last_node = trie_get_node(self, node_id);
-    if (last_node.base == NULL_ID) {
-        log_debug("last_node.base == NULL_ID, node_id = %d\n", node_id);
+    if (last_node.base == NULL_NODE_ID) {
+        log_debug("last_node.base == NULL_NODE_ID, node_id = %d\n", node_id);
         return false;
     }
     
@@ -636,7 +636,7 @@ bool trie_add_at_index(trie_t *self, uint32_t node_id, char *key, uint32_t data)
         node_id = trie_get_transition_index(self, last_node, *ptr);
         log_debug("node_id=%d, last_node.base=%d, last_node.check=%d, char_index=%d\n", node_id, last_node.base, last_node.check, trie_get_char_index(self, *ptr));
 
-        if (node_id != NULL_ID) {
+        if (node_id != NULL_NODE_ID) {
             trie_make_room_for(self, node_id);
         }
 
@@ -660,7 +660,7 @@ bool trie_add_at_index(trie_t *self, uint32_t node_id, char *key, uint32_t data)
 
 bool trie_add(trie_t *self, char *key, uint32_t data) {
     if (strlen(key) == 0) return false;
-    return trie_add_at_index(self, ROOT_ID, key, data);
+    return trie_add_at_index(self, ROOT_NODE_ID, key, data);
 }
 
 bool trie_add_suffix(trie_t *self, char *key, uint32_t data) {
@@ -669,8 +669,8 @@ bool trie_add_suffix(trie_t *self, char *key, uint32_t data) {
 
     uint32_t node_id = trie_get_transition_index(self, root, '\0');
     trie_node_t node = trie_get_node(self, node_id);
-    if (node.check != ROOT_ID) {
-        node_id = trie_add_transition(self, ROOT_ID, '\0');
+    if (node.check != ROOT_NODE_ID) {
+        node_id = trie_add_transition(self, ROOT_NODE_ID, '\0');
     }
 
     char *suffix = utf8_reversed_string(key); 
@@ -681,15 +681,15 @@ bool trie_add_suffix(trie_t *self, char *key, uint32_t data) {
 
 
 uint32_t trie_get_prefix_from_index(trie_t *self, char *key, size_t len, uint32_t i) {
-    if (key == NULL) return NULL_ID;
+    if (key == NULL) return NULL_NODE_ID;
 
     unsigned char *ptr = (unsigned char *)key;
 
     uint32_t node_id = i;
     trie_node_t node = trie_get_node(self, i);
-    if (node.base == NULL_ID) return NULL_ID;
+    if (node.base == NULL_NODE_ID) return NULL_NODE_ID;
 
-    uint32_t next_id = NULL_ID;
+    uint32_t next_id = NULL_NODE_ID;
 
     // Include NUL-byte. It may be stored if this phrase is a prefix of a longer one
 
@@ -698,7 +698,7 @@ uint32_t trie_get_prefix_from_index(trie_t *self, char *key, size_t len, uint32_
         node = trie_get_node(self, next_id);
 
         if (node.check != node_id) {
-            return NULL_ID;
+            return NULL_NODE_ID;
         }
     }
 
@@ -707,21 +707,21 @@ uint32_t trie_get_prefix_from_index(trie_t *self, char *key, size_t len, uint32_
 }
 
 uint32_t trie_get_prefix_len(trie_t *self, char *key, size_t len) {
-    return trie_get_prefix_from_index(self, key, len, ROOT_ID);
+    return trie_get_prefix_from_index(self, key, len, ROOT_NODE_ID);
 }
 
 uint32_t trie_get_prefix(trie_t *self, char *key) {
-    return trie_get_prefix_from_index(self, key, strlen(key), ROOT_ID);
+    return trie_get_prefix_from_index(self, key, strlen(key), ROOT_NODE_ID);
 }
 
 uint32_t trie_get_from_index(trie_t *self, char *word, size_t len, uint32_t i) {
-    if (word == NULL) return NULL_ID;
+    if (word == NULL) return NULL_NODE_ID;
 
     unsigned char *ptr = (unsigned char *)word;
 
     uint32_t node_id = i;
     trie_node_t node = trie_get_node(self, i);
-    if (node.base == NULL_ID) return NULL_ID;
+    if (node.base == NULL_NODE_ID) return NULL_NODE_ID;
 
     uint32_t next_id;
 
@@ -732,7 +732,7 @@ uint32_t trie_get_from_index(trie_t *self, char *word, size_t len, uint32_t i) {
         node = trie_get_node(self, next_id);
 
         if (node.check != node_id) {
-            return NULL_ID;
+            return NULL_NODE_ID;
         }
 
         if (node.check == node_id && node.base < 0) {
@@ -749,7 +749,7 @@ uint32_t trie_get_from_index(trie_t *self, char *word, size_t len, uint32_t i) {
             if (tail_match == 0) {
                 return next_id;
             } else {
-                return NULL_ID;
+                return NULL_NODE_ID;
             }
 
         }
@@ -761,12 +761,12 @@ uint32_t trie_get_from_index(trie_t *self, char *word, size_t len, uint32_t i) {
 }
 
 uint32_t trie_get_len(trie_t *self, char *word, size_t len) {
-    return trie_get_from_index(self, word, len, ROOT_ID);
+    return trie_get_from_index(self, word, len, ROOT_NODE_ID);
 }
 
 uint32_t trie_get(trie_t *self, char *word) {
     size_t word_len = strlen(word);
-    return trie_get_from_index(self, word, word_len, ROOT_ID);
+    return trie_get_from_index(self, word, word_len, ROOT_NODE_ID);
 }
 
 /*
diff --git a/src/trie.h b/src/trie.h
index c4a2097a..186bad45 100644
--- a/src/trie.h
+++ b/src/trie.h
@@ -31,9 +31,9 @@ extern "C" {
 #include "string_utils.h"
 
 #define TRIE_SIGNATURE 0xABABABAB
-#define NULL_ID 0
+#define NULL_NODE_ID 0
 #define FREE_LIST_ID 1
-#define ROOT_ID 2
+#define ROOT_NODE_ID 2
 #define TRIE_POOL_BEGIN 3
 #define DEFAULT_NODE_ARRAY_SIZE 32
 
diff --git a/src/trie_search.c b/src/trie_search.c
index d81ff518..1451dcb5 100644
--- a/src/trie_search.c
+++ b/src/trie_search.c
@@ -20,7 +20,7 @@ phrase_array *trie_search(trie_t *self, char *text) {
     const uint8_t *fail_ptr = ptr;
     trie_node_t node = trie_get_root(self), last_node = node;
 
-    uint32_t node_id = ROOT_ID;
+    uint32_t node_id = ROOT_NODE_ID;
     uint32_t next_id;
 
     bool match = false;
@@ -78,7 +78,7 @@ phrase_array *trie_search(trie_t *self, char *text) {
                 }
                 fail_ptr = ptr;
                 last_node = node = trie_get_root(self);
-                node_id = ROOT_ID;
+                node_id = ROOT_NODE_ID;
                 phrase_start = phrase_len = 0;
                 last_state = state;
                 match = false;
@@ -209,7 +209,7 @@ phrase_array *trie_search_tokens(trie_t *self, char *str, token_array *tokens) {
     phrase_array *phrases = phrase_array_new();
 
     trie_node_t node = trie_get_root(self), last_node = node;
-    uint32_t node_id = ROOT_ID, last_node_id = ROOT_ID;
+    uint32_t node_id = ROOT_NODE_ID, last_node_id = ROOT_NODE_ID;
 
     uint32_t data;
 
@@ -244,7 +244,7 @@ phrase_array *trie_search_tokens(trie_t *self, char *str, token_array *tokens) {
             if (node.check != last_node_id && last_node.base >= 0) {
                 log_debug("Fell off trie. last_node_id=%d and node.check=%d\n", last_node_id, node.check);
                 node = trie_get_root(self);
-                node_id = ROOT_ID;
+                node_id = ROOT_NODE_ID;
                 break;
             } else if (node.base < 0) {
                 log_debug("Searching tail at index %d\n", i);
@@ -268,7 +268,7 @@ phrase_array *trie_search_tokens(trie_t *self, char *str, token_array *tokens) {
                     int tail_search_result = trie_node_search_tail_tokens(self, node, str, tokens, ptr_len, i+1);
                     if (tail_search_result == -1) {
                         node = trie_get_root(self);
-                        node_id = ROOT_ID;
+                        node_id = ROOT_NODE_ID;
                         break;
                     } else {
                         phrase_len = tail_search_result - phrase_start + 1;
@@ -279,7 +279,7 @@ phrase_array *trie_search_tokens(trie_t *self, char *str, token_array *tokens) {
 
                 } else {
                     node = trie_get_root(self);
-                    node_id = ROOT_ID;
+                    node_id = ROOT_NODE_ID;
                     break;
                 }
             }
@@ -295,7 +295,7 @@ phrase_array *trie_search_tokens(trie_t *self, char *str, token_array *tokens) {
                 last_match_index = -1;
                 phrase_start = 0;
                 last_node = trie_get_root(self);
-                last_node_id = ROOT_ID;
+                last_node_id = ROOT_NODE_ID;
                 continue;
             } else if (last_state == SEARCH_STATE_PARTIAL_MATCH) {
                 log_debug("last_state == SEARCH_STATE_PARTIAL_MATCH\n");
@@ -307,7 +307,7 @@ phrase_array *trie_search_tokens(trie_t *self, char *str, token_array *tokens) {
                 log_debug("Plain token=%.*s\n", token.len, str + token.offset);
             }
             last_node = trie_get_root(self);
-            last_node_id = ROOT_ID;
+            last_node_id = ROOT_NODE_ID;
         } else {
 
             state = SEARCH_STATE_PARTIAL_MATCH;
@@ -346,7 +346,7 @@ phrase_array *trie_search_tokens(trie_t *self, char *str, token_array *tokens) {
                 phrase_array_push(phrases, (phrase_t){phrase_start, last_match_index - phrase_start + 1, data});
                 last_match_index = -1; 
                 last_node = node = trie_get_root(self);
-                last_node_id = node_id = ROOT_ID;
+                last_node_id = node_id = ROOT_NODE_ID;
                 state = SEARCH_STATE_BEGIN;
             } else {
                 log_debug("Has continuation, node_id=%d\n", continuation_id);
@@ -365,12 +365,12 @@ phrase_array *trie_search_tokens(trie_t *self, char *str, token_array *tokens) {
 }
 
 phrase_t trie_search_suffixes(trie_t *self, char *word) {
-    uint32_t node_id = ROOT_ID, last_node_id = ROOT_ID;
+    uint32_t node_id = ROOT_NODE_ID, last_node_id = ROOT_NODE_ID;
     trie_node_t last_node = trie_get_root(self);
     node_id = trie_get_transition_index(self, last_node, '\0');
     trie_node_t node = trie_get_node(self, node_id);
 
-    if (node.check != ROOT_ID) {
+    if (node.check != ROOT_NODE_ID) {
         return (phrase_t){0, 0, 0};
     } else {
         last_node = node;
@@ -467,7 +467,7 @@ phrase_t trie_search_suffixes(trie_t *self, char *word) {
 }
 
 phrase_t trie_search_prefixes(trie_t *self, char *word) {
-    uint32_t node_id = ROOT_ID, last_node_id = node_id;
+    uint32_t node_id = ROOT_NODE_ID, last_node_id = node_id;
     trie_node_t node = trie_get_root(self), last_node = node;
 
     uint32_t value = 0, phrase_start = 0, phrase_len = 0;