diff --git a/joy/__main__.py b/joy/__main__.py
index f6f2909..cdf0f41 100644
--- a/joy/__main__.py
+++ b/joy/__main__.py
@@ -18,7 +18,7 @@
 #    along with Thun.  If not see <http://www.gnu.org/licenses/>.
 #
 import argparse, io, pkg_resources
-from .library import initialize, inscribe
+from .library import initialize, inscribe, Def
 from .joy import repl, interp
 from .utils.pretty_print import trace
 
@@ -68,4 +68,8 @@ under certain conditions; type "sharing" for details.
 Type "words" to see a list of all words, and "[<name>] help" to print the
 docs for a word.
 ''')
-stack = j(dictionary=initialize())
+
+dictionary=initialize()
+for def_stream in args.defs:
+    Def.load_definitions(def_stream, dictionary)
+stack = j(dictionary=dictionary)
diff --git a/joy/library.py b/joy/library.py
index 47d919b..90d7a9c 100644
--- a/joy/library.py
+++ b/joy/library.py
@@ -323,6 +323,14 @@ class Def(DefinitionWrapper):
         self.__doc__ = expression_to_string(body)
         self._compiled = None
 
+    @classmethod
+    def load_definitions(class_, stream, dictionary):
+        for line in stream:
+            if line.lstrip().startswith('#'):
+                continue
+            name, body = text_to_expression(line)
+            inscribe(class_(name, body), dictionary)
+
 
 def _text_to_defs(text):
     return (