diff --git a/src/groth/mod.rs b/src/groth/mod.rs
index 18d9506..bfdfd5e 100644
--- a/src/groth/mod.rs
+++ b/src/groth/mod.rs
@@ -307,7 +307,7 @@ pub fn prepare_verifying_key<E: Engine>(
     }
 }
 
-pub fn verify<E: Engine, C: Witness<E>, F: FnOnce(&mut ConstraintSystem<E>) -> C>(
+pub fn verify<E: Engine, C: Input<E>, F: FnOnce(&mut ConstraintSystem<E>) -> C>(
     e: &E,
     circuit: F,
     proof: &Proof<E>,
diff --git a/src/groth/tests/mod.rs b/src/groth/tests/mod.rs
index e486c5f..908de83 100644
--- a/src/groth/tests/mod.rs
+++ b/src/groth/tests/mod.rs
@@ -6,12 +6,12 @@ struct RootCircuit<E: Engine> {
 }
 
 impl<E: Engine> Circuit<E> for RootCircuit<E> {
-    type WitnessMap = RootWitness<E>;
+    type InputMap = RootInput<E>;
 
     fn synthesize<CS: ConstraintSystem<E>>(self,
                                            e: &E,
                                            cs: &mut CS)
-                                           -> Self::WitnessMap
+                                           -> Self::InputMap
     {
         let root_var = cs.alloc(self.root);
 
@@ -31,19 +31,19 @@ impl<E: Engine> Circuit<E> for RootCircuit<E> {
             cur = new;
         }
 
-        RootWitness {
+        RootInput {
             num: cur_val,
             num_var: cur
         }
     }
 }
 
-struct RootWitness<E: Engine> {
+struct RootInput<E: Engine> {
     num: E::Fr,
     num_var: Variable
 }
 
-impl<E: Engine> Witness<E> for RootWitness<E> {
+impl<E: Engine> Input<E> for RootInput<E> {
     fn synthesize<CS: PublicConstraintSystem<E>>(
         self,
         e: &E,
@@ -96,7 +96,7 @@ fn test_snark_system<E: Engine, R: Rng>(
 
     // verify proof
     assert!(verify(e, |cs| {
-        RootWitness {
+        RootInput {
             num: E::Fr::from_str(e, "1267650600228229401496703205376").unwrap(),
             num_var: cs.alloc(E::Fr::one(e))
         }
@@ -104,7 +104,7 @@ fn test_snark_system<E: Engine, R: Rng>(
 
     // verify invalid proof
     assert!(!verify(e, |cs| {
-        RootWitness {
+        RootInput {
             num: E::Fr::from_str(e, "1267650600228229401496703205375").unwrap(),
             num_var: cs.alloc(E::Fr::one(e))
         }
@@ -181,7 +181,7 @@ fn test_snark_system<E: Engine, R: Rng>(
 
     // verify fake proof
     assert!(verify(e, |cs| {
-        RootWitness {
+        RootInput {
             num: E::Fr::from_str(e, "100").unwrap(),
             num_var: cs.alloc(E::Fr::one(e))
         }
@@ -189,7 +189,7 @@ fn test_snark_system<E: Engine, R: Rng>(
 
     // verify fake proof with wrong input
     assert!(!verify(e, |cs| {
-        RootWitness {
+        RootInput {
             num: E::Fr::from_str(e, "101").unwrap(),
             num_var: cs.alloc(E::Fr::one(e))
         }
diff --git a/src/lib.rs b/src/lib.rs
index d72b212..691e1bf 100644
--- a/src/lib.rs
+++ b/src/lib.rs
@@ -118,14 +118,14 @@ impl<'a, E: Engine> LinearCombination<'a, E> {
 }
 
 pub trait Circuit<E: Engine> {
-    type WitnessMap: Witness<E>;
+    type InputMap: Input<E>;
 
     /// Synthesize the circuit into a rank-1 quadratic constraint system
     #[must_use]
-    fn synthesize<CS: ConstraintSystem<E>>(self, engine: &E, cs: &mut CS) -> Self::WitnessMap;
+    fn synthesize<CS: ConstraintSystem<E>>(self, engine: &E, cs: &mut CS) -> Self::InputMap;
 }
 
-pub trait Witness<E: Engine> {
+pub trait Input<E: Engine> {
     /// Synthesize the circuit, except with additional access to public input
     /// variables
     fn synthesize<CS: PublicConstraintSystem<E>>(self, engine: &E, cs: &mut CS);