diff --git a/dictionary.py b/dictionary.py
new file mode 100644
index 0000000..5327077
--- /dev/null
+++ b/dictionary.py
@@ -0,0 +1,80 @@
+#!/usr/bin/python
+
+
+WORDLE_LENGTH = 5
+
+
+_wordle_dictionary = set()
+
+
+_invalid_words = set(
+    [
+        "amala",
+        "arara",
+        "araru",
+        "araua",
+        "arawa",
+        "balak",
+        "batak",
+        "bayal",
+        "beala",
+        "beata",
+        "beele",
+        "boily",
+        "bolty",
+        "bruke",
+        "carlo",
+        "caroa",
+        "carot",
+        "carum",
+        "divet",
+        "doray",
+        "erept",
+        "fikie",
+        "genae",
+        "ghole",
+        "gotra",
+        "hirse",
+        "hyrse",
+        "katat",
+        "korah",
+        "macco",
+        "mitra",
+        "muang",
+        "nurry",
+        "odell",
+        "odell",
+        "petro",
+        "pindy",
+        "quito",
+        "retan",
+        "roter",
+        "sisel",
+        "skeel",
+        "staia",
+        "stail",
+        "sussy",
+        "tebet",
+        "telae",
+        "theet",
+        "undig",
+        "uninn",
+        "unkin",
+        "vedet",
+        "whalm",
+        "whaly",
+    ]
+)
+
+
+def words():
+    if not _wordle_dictionary:
+        with open("words_alpha.txt") as word_file:
+            all_words = word_file.read().split()
+        _wordle_dictionary.update(
+            filter(
+                lambda w: len(w) == WORDLE_LENGTH and w not in _invalid_words, all_words
+            )
+        )
+
+    return _wordle_dictionary
diff --git a/wordle.py b/wordle.py
index 9d90b90..af1cb9a 100644
--- a/wordle.py
+++ b/wordle.py
@@ -6,7 +6,7 @@ import string
 from enum import Enum
 from collections import defaultdict
 
-WORDLE_LENGTH = 5
+import dictionary
 
 
 class LetterResult(Enum):
@@ -24,92 +24,17 @@ class InvalidWord(Exception):
     pass
 
 
-_wordle_dictionary = set()
-
-
-_invalid_words = set(
-    [
-        "amala",
-        "arara",
-        "araru",
-        "araua",
-        "arawa",
-        "balak",
-        "batak",
-        "bayal",
-        "beala",
-        "beata",
-        "beele",
-        "boily",
-        "bolty",
-        "bruke",
-        "carlo",
-        "caroa",
-        "carot",
-        "carum",
-        "divet",
-        "doray",
-        "erept",
-        "fikie",
-        "genae",
-        "ghole",
-        "gotra",
-        "hirse",
-        "hyrse",
-        "katat",
-        "korah",
-        "macco",
-        "mitra",
-        "muang",
-        "nurry",
-        "odell",
-        "odell",
-        "petro",
-        "pindy",
-        "quito",
-        "retan",
-        "roter",
-        "sisel",
-        "skeel",
-        "staia",
-        "stail",
-        "sussy",
-        "tebet",
-        "telae",
-        "theet",
-        "undig",
-        "uninn",
-        "unkin",
-        "vedet",
-        "whalm",
-        "whaly",
-    ]
-)
-
-
-def dictionary():
-    if not _wordle_dictionary:
-        with open("words_alpha.txt") as word_file:
-            all_words = word_file.read().split()
-        _wordle_dictionary.update(
-            filter(
-                lambda w: len(w) == WORDLE_LENGTH and w not in _invalid_words, all_words
-            )
-        )
-
-    return _wordle_dictionary
-
 
 def select_word():
-    return random.choice(list(dictionary()))
+    return random.choice(list(dictionary.words()))
 
 
 def grade_word(target, guess):
     # We don't check word length, since all valid words are 5 letters.
-    if guess not in dictionary():
+    if guess not in dictionary.words():
         raise InvalidWord(f"{guess} is not a valid Wordle.")
 
-    result = [LetterResult.UNKNOWN] * WORDLE_LENGTH
+    result = [LetterResult.UNKNOWN] * dictionary.WORDLE_LENGTH
 
     # We copy target, and remove letters if we find them. This handles duplicate letters correctly.
     # For example, if the target is "pulls" and we guess "apple", only the first "p" should be a
@@ -117,12 +42,12 @@ def grade_word(target, guess):
     remaining = list(target)
 
     # Find all correct results first.
-    for i in range(WORDLE_LENGTH):
+    for i in range(dictionary.WORDLE_LENGTH):
         if target[i] == guess[i]:
             result[i] = LetterResult.CORRECT
             remaining.remove(guess[i])
 
-    for i in range(WORDLE_LENGTH):
+    for i in range(dictionary.WORDLE_LENGTH):
         if result[i] == LetterResult.UNKNOWN:
             if guess[i] in remaining:
                 # Letter is in the wrong place.
@@ -198,7 +123,7 @@ def score_word(position_matches, word_matches, word):
     return result
 
 
-def scored_words(wordle_dictionary=dictionary()):
+def scored_words(wordle_dictionary=dictionary.words()):
     # word: score
     scored_words = dict()
 
@@ -216,9 +141,9 @@ def scored_words(wordle_dictionary=dictionary()):
 class Constraints:
     def __init__(self):
         # Array of known letters in result with None for unknown.
-        self.correct = [None] * WORDLE_LENGTH
+        self.correct = [None] * dictionary.WORDLE_LENGTH
         # Array with per-letter sets of known bad letters.
-        self.incorrect = [set() for _ in range(WORDLE_LENGTH)]
+        self.incorrect = [set() for _ in range(dictionary.WORDLE_LENGTH)]
         # Dict of letter -> int with minimum required count of letter in word.
         self.count = defaultdict(int)
         # If letter is present in set, value in min is both min and max.
@@ -272,7 +197,7 @@ class Constraints:
         return True
 
 
-def filter_dictionary(constraints, wordle_dictionary=dictionary()):
+def filter_dictionary(constraints, wordle_dictionary=dictionary.words()):
     return set(filter(lambda w: constraints.matches(w), wordle_dictionary))