diff --git a/src/functions.py b/src/functions.py
index e7ee6719f7abe89d1a2e9e7e4be2aa2cfd6f2f03..b5e110b10de8bcc740b4596b077c54f0ebd2e4ad 100644
--- a/src/functions.py
+++ b/src/functions.py
@@ -4,13 +4,13 @@ import pymbolic.primitives as primitives
 
 
 def sin(x):
-    return primitives.Call(primitives.ElementLookup(primitives.Variable("math"), "sin"), (x,))
+    return primitives.Call(primitives.Lookup(primitives.Variable("math"), "sin"), (x,))
 def cos(x):
-    return primitives.Call(primitives.ElementLookup(primitives.Variable("math"), "cos"), (x,))
+    return primitives.Call(primitives.Lookup(primitives.Variable("math"), "cos"), (x,))
 def tan(x):
-    return primitives.Call(primitives.ElementLookup(primitives.Variable("math"), "tan"), (x,))
+    return primitives.Call(primitives.Lookup(primitives.Variable("math"), "tan"), (x,))
 def log(x):
-    return primitives.Call(primitives.ElementLookup(primitives.Variable("math"), "log"), (x,))
+    return primitives.Call(primitives.Lookup(primitives.Variable("math"), "log"), (x,))
 def exp(x):
-    return primitives.Call(primitives.ElementLookup(primitives.Variable("math"), "exp"), (x,))
+    return primitives.Call(primitives.Lookup(primitives.Variable("math"), "exp"), (x,))
 
diff --git a/src/mapper/differentiator.py b/src/mapper/differentiator.py
index e19edc3dadbc9585621f1785540e1b59565afa0f..8f613f54ffae3ad04258e1a4debedaf9c7981b4e 100644
--- a/src/mapper/differentiator.py
+++ b/src/mapper/differentiator.py
@@ -15,7 +15,7 @@ def map_math_functions_by_name(i, func, pars):
         raise RuntimeError, "No derivative of non-constant function "+str(func)
 
     def make_f(name):
-        return primitives.ElementLookup(primitives.Variable("math"), name)
+        return primitives.Lookup(primitives.Variable("math"), name)
 
     if f is math.sin and len(pars) == 1:
         return make_f("cos")(*pars)
diff --git a/src/parser.py b/src/parser.py
index f7a7e384997ba7a4e91c27a475da34bd1cd3390e..cb77d3c02951cbd690e109b73898eac96a86fe90 100644
--- a/src/parser.py
+++ b/src/parser.py
@@ -112,7 +112,7 @@ def parse(expr_str):
             elif next_tag is _dot and _PREC_CALL > min_precedence:
                 pstate.advance()
                 pstate.expect(_identifier)
-                left_exp = primitives.ElementLookup(left_exp, pstate.next_str())
+                left_exp = primitives.Lookup(left_exp, pstate.next_str())
                 pstate.advance()
                 did_something = True
             elif next_tag is _plus and _PREC_PLUS > min_precedence:
diff --git a/src/primitives.py b/src/primitives.py
index 976baf78b6815c77daf911557aba3e2655b3c6c3..d139bbb1f4ee097b3c3fb9deadb00c00b4cf42de 100644
--- a/src/primitives.py
+++ b/src/primitives.py
@@ -237,7 +237,7 @@ class Subscript(AlgebraicLeaf):
 
 
 
-class ElementLookup(AlgebraicLeaf):
+class Lookup(AlgebraicLeaf):
     def __init__(self, aggregate, name):
         self.aggregate = aggregate
         self.name = name
@@ -246,7 +246,7 @@ class ElementLookup(AlgebraicLeaf):
         return self.aggregate, self.name
 
     def __eq__(self, other):
-        return isinstance(other, ElementLookup) \
+        return isinstance(other, Lookup) \
                and (self.aggregate == other.aggregate) \
                and (self.name == other.name)
 
@@ -426,7 +426,7 @@ class Power(Expression):
 
 # intelligent makers ---------------------------------------------------------
 def make_variable(var_or_string):
-    if not isinstance(var_or_string, Variable):
+    if not isinstance(var_or_string, Expression):
         return Variable(var_or_string)
     else:
         return var_or_string