diff --git a/source/lectures/ME400_Lecture_18.ipynb b/source/lectures/ME400_Lecture_18.ipynb
index 24b3e72..78529b6 100644
--- a/source/lectures/ME400_Lecture_18.ipynb
+++ b/source/lectures/ME400_Lecture_18.ipynb
@@ -1168,7 +1168,7 @@
    "cell_type": "markdown",
    "metadata": {},
    "source": [
-    "Note something important: the original expression was named `f`.  To keep names straight, I recommend naming any *lambdified* expression `f` in the form `f_fun` `f_lam` to indicate its use as a function.\n",
+    "Note something important: the original expression was named `f`.  To keep names straight, I recommend naming any *lambdified* expression `f` in the form `f_fun` to indicate its use as a function.\n",
     "\n",
     "The result works by default for `ndarrays`:"
    ]