diff --git a/lib/lin_common.ml b/lib/lin_common.ml
index d9f127aef..79359efd4 100644
--- a/lib/lin_common.ml
+++ b/lib/lin_common.ml
@@ -133,19 +133,19 @@ let val_ name value fntyp =
 let val_freq freq name value fntyp =
   (freq, Elem (name, fntyp, value))
 
-module type ApiSpec = sig
+module type InterfaceSpec = sig
   type t
   val init : unit -> t
   val cleanup : t -> unit
   val api : (int * t elem) list
 end
 
-module MakeCmd (ApiSpec : ApiSpec) : Lin_internal.CmdSpec = struct
+module Make_test_repr (InterfaceSpec : InterfaceSpec) : Lin_internal.TestRepr = struct
 
-  type t = ApiSpec.t
+  type t = InterfaceSpec.t
 
-  let init = ApiSpec.init
-  let cleanup = ApiSpec.cleanup
+  let init = InterfaceSpec.init
+  let cleanup = InterfaceSpec.cleanup
 
   (* Typed argument list and return type descriptor *)
   module Args = struct
@@ -251,7 +251,7 @@ module MakeCmd (ApiSpec : ApiSpec) : Lin_internal.CmdSpec = struct
         (wgt, gen_args_of_desc fdesc >>= fun args ->
          let print = gen_printer name fdesc in
          let shrink = gen_shrinker_of_desc fdesc in
-         return (Cmd (name, args, rty, print, shrink, f)))) ApiSpec.api
+         return (Cmd (name, args, rty, print, shrink, f)))) InterfaceSpec.api
 
   let gen_cmd : cmd QCheck.Gen.t = QCheck.Gen.frequency api
 
diff --git a/lib/lin_common.mli b/lib/lin_common.mli
index b972cc653..aa5366280 100644
--- a/lib/lin_common.mli
+++ b/lib/lin_common.mli
@@ -144,10 +144,10 @@ val seq : ('a, 'c, 's, combinable) ty -> ('a Seq.t, 'c, 's, combinable) ty
     and have their elements generated by the [t] combinator. *)
 
 val t : ('a, constructible, 'a, noncombinable) ty
-(** The [t] combinator represents the type [ApiSpec.t] of the system under test. *)
+(** The [t] combinator represents the type [InterfaceSpec.t] of the system under test. *)
 
 val state : ('a, constructible, 'a, noncombinable) ty
-(** The [state] combinator represents the type [ApiSpec.t] of the system under test.
+(** The [state] combinator represents the type [InterfaceSpec.t] of the system under test.
     It is an alias for the [t] combinator. *)
 
 val or_exn :
@@ -219,7 +219,7 @@ val val_freq : int -> string -> 'f -> ('f, 'r, 's) Fun.fn -> int * 's elem
 
 
 (** The required description of a module signature *)
-module type ApiSpec =
+module type InterfaceSpec =
   sig
     type t
     (** The type of the system under test *)
@@ -237,6 +237,7 @@ module type ApiSpec =
 
 (** {1 Generation of linearizability testing module from an API} *)
 
-module MakeCmd : functor (Spec : ApiSpec) -> Lin_internal.CmdSpec
+module Make_test_repr : functor (Spec : InterfaceSpec) ->
+  Lin_internal.TestRepr
 (** Functor to map a combinator-based module signature description
     into a raw [Lin] description *)
diff --git a/lib/lin_domain.ml b/lib/lin_domain.ml
index 424cf92ff..da6155f42 100644
--- a/lib/lin_domain.ml
+++ b/lib/lin_domain.ml
@@ -1,6 +1,6 @@
 open Lin_base
 
-module Make_internal (Spec : Lin_internal.CmdSpec) = struct
+module Make_internal (Spec : Lin_internal.TestRepr) = struct
   module M = Lin_internal.Make(Spec)
   include M
 
@@ -35,5 +35,5 @@ module Make_internal (Spec : Lin_internal.CmdSpec) = struct
     neg_lin_test ~rep_count:50 ~count ~retries:3 ~name ~lin_prop:lin_prop_domain
 end
 
-module Make (Spec : Lin_common.ApiSpec) =
-  Make_internal(Lin_common.MakeCmd(Spec))
+module Make (Spec : Lin_common.InterfaceSpec) =
+  Make_internal(Lin_common.Make_test_repr(Spec))
diff --git a/lib/lin_effect.ml b/lib/lin_effect.ml
index a3fd50fc6..77745da3f 100644
--- a/lib/lin_effect.ml
+++ b/lib/lin_effect.ml
@@ -33,10 +33,10 @@ let start_sched main =
 let fork f = perform (Fork f)
 let yield () = perform Yield
 
-module Make_internal (Spec : Lin_internal.CmdSpec) = struct
+module Make_internal (Spec : Lin_internal.TestRepr) = struct
 
 
-  (** A refined [CmdSpec] specification with generator-controlled [Yield] effects *)
+  (** A refined [TestRepr] specification with generator-controlled [Yield] effects *)
   module EffSpec
   = struct
     open QCheck
@@ -122,5 +122,5 @@ module Make_internal (Spec : Lin_internal.CmdSpec) = struct
       arb_cmd_triple (Util.repeat rep_count lin_prop_effect)
 end
 
-module Make (Spec : Lin_common.ApiSpec) =
-  Make_internal(Lin_common.MakeCmd(Spec))
+module Make (Spec : Lin_common.InterfaceSpec) =
+  Make_internal(Lin_common.Make_test_repr(Spec))
diff --git a/lib/lin_internal.ml b/lib/lin_internal.ml
index f309ed343..4bc4842db 100644
--- a/lib/lin_internal.ml
+++ b/lib/lin_internal.ml
@@ -1,7 +1,7 @@
 open QCheck
 include Util
 
-module type CmdSpec = sig
+module type TestRepr = sig
   type t
   (** The type of the system under test *)
 
@@ -39,7 +39,7 @@ end
 
 (** A functor to create test setups, for all backends (Domain, Thread and Effect).
     We use it below, but it can also be used independently *)
-module Make(Spec : CmdSpec)
+module Make(Spec : TestRepr)
   = struct
 
   (* plain interpreter of a cmd list *)
diff --git a/lib/lin_thread.ml b/lib/lin_thread.ml
index 3ec96eb41..253b027a2 100644
--- a/lib/lin_thread.ml
+++ b/lib/lin_thread.ml
@@ -1,6 +1,6 @@
 open Lin_base
 
-module Make_internal (Spec : Lin_internal.CmdSpec) = struct
+module Make_internal (Spec : Lin_internal.TestRepr) = struct
   module M = Lin_internal.Make(Spec)
   include M
 
@@ -42,5 +42,5 @@ module Make_internal (Spec : Lin_internal.CmdSpec) = struct
     neg_lin_test ~rep_count:100 ~count ~retries:5 ~name ~lin_prop:lin_prop_thread
 end
 
-module Make (Spec : Lin_common.ApiSpec) =
-  Make_internal(Lin_common.MakeCmd(Spec))
+module Make (Spec : Lin_common.InterfaceSpec) =
+  Make_internal(Lin_common.Make_test_repr(Spec))
diff --git a/src/atomic/lin_tests_dsl.ml b/src/atomic/lin_tests_dsl.ml
index 57a2d578e..2e40e2bdf 100644
--- a/src/atomic/lin_tests_dsl.ml
+++ b/src/atomic/lin_tests_dsl.ml
@@ -1,4 +1,4 @@
-module Atomic_spec : Lin_base.ApiSpec = struct
+module Atomic_spec : Lin_base.InterfaceSpec = struct
   open Lin_base (* FIXME add Gen.nat *)
   type t = int Atomic.t
   let init () = Atomic.make 0
diff --git a/src/hashtbl/lin_tests_dsl.ml b/src/hashtbl/lin_tests_dsl.ml
index 3b4f49403..ad47e6dc8 100644
--- a/src/hashtbl/lin_tests_dsl.ml
+++ b/src/hashtbl/lin_tests_dsl.ml
@@ -1,7 +1,7 @@
 (* ********************************************************************** *)
 (*                      Tests of thread-unsafe [Hashtbl]                  *)
 (* ********************************************************************** *)
-module HConf (*: Lin_base.ApiSpec*) =
+module HConf (*: Lin_base.InterfaceSpec*) =
 struct
   type t = (char, int) Hashtbl.t
 
diff --git a/src/neg_tests/lin_tests_dsl_common.ml b/src/neg_tests/lin_tests_dsl_common.ml
index e11b163f4..3d7bed149 100644
--- a/src/neg_tests/lin_tests_dsl_common.ml
+++ b/src/neg_tests/lin_tests_dsl_common.ml
@@ -24,7 +24,7 @@ module Sut_int64 =
     let decr r = add r Int64.minus_one                (* buggy: not atomic *)
 end
 
-module Ref_int_spec : ApiSpec = struct
+module Ref_int_spec : InterfaceSpec = struct
   type t = int ref
   let init () = Sut_int.init ()
   let cleanup _ = ()
@@ -38,7 +38,7 @@ module Ref_int_spec : ApiSpec = struct
     ]
   end
 
-module Ref_int64_spec : ApiSpec = struct
+module Ref_int64_spec : InterfaceSpec = struct
   type t = int64 ref
   let init () = Sut_int64.init ()
   let cleanup _ = ()
@@ -59,7 +59,7 @@ module RT_int64_domain = Lin_domain.Make(Ref_int64_spec)
 (**                  Tests of the buggy concurrent list CList              *)
 (** ********************************************************************** *)
 
-module CList_spec_int : ApiSpec =
+module CList_spec_int : InterfaceSpec =
 struct
   type t = int CList.conc_list Atomic.t
   let init () = CList.list_init 0
@@ -71,7 +71,7 @@ struct
     ]
   end
 
-module CList_spec_int64 : ApiSpec =
+module CList_spec_int64 : InterfaceSpec =
 struct
   type t = int64 CList.conc_list Atomic.t
   let init () = CList.list_init Int64.zero
diff --git a/src/neg_tests/lin_tests_dsl_effect.ml b/src/neg_tests/lin_tests_dsl_effect.ml
index 97f0a6dd5..c3a363bf2 100644
--- a/src/neg_tests/lin_tests_dsl_effect.ml
+++ b/src/neg_tests/lin_tests_dsl_effect.ml
@@ -13,7 +13,7 @@ module Sut_int' = struct
   let add r i = let old = !r in Lin_effect.yield (); set r (old+i)
 end
 
-module Ref_int'_spec : ApiSpec = struct
+module Ref_int'_spec : InterfaceSpec = struct
   type t = int ref
   let init () = Sut_int'.init ()
   let cleanup _ = ()
@@ -34,7 +34,7 @@ module Sut_int64' = struct
   let add r i = let old = !r in Lin_effect.yield (); set r (Int64.add old i)
 end
 
-module Ref_int64'_spec : ApiSpec = struct
+module Ref_int64'_spec : InterfaceSpec = struct
   type t = int64 ref
   let init () = Sut_int64'.init ()
   let cleanup _ = ()
@@ -51,7 +51,7 @@ module RT_int64_effect = Lin_effect.Make(Ref_int64_spec)
 module RT_int64'_effect = Lin_effect.Make(Ref_int64'_spec)
 
 
-module CList_spec_int' : ApiSpec =
+module CList_spec_int' : InterfaceSpec =
 struct
   type t = int CList.conc_list Atomic.t
   let init () = CList.list_init 0
@@ -62,7 +62,7 @@ struct
       val_ "CList.member"   CList.member  (t @-> int @-> returning bool);
     ]
   end
-module CList_spec_int64' : ApiSpec =
+module CList_spec_int64' : InterfaceSpec =
 struct
   type t = int64 CList.conc_list Atomic.t
   let init () = CList.list_init Int64.zero
diff --git a/src/queue/lin_tests_dsl.ml b/src/queue/lin_tests_dsl.ml
index 3c3621515..e104d2326 100644
--- a/src/queue/lin_tests_dsl.ml
+++ b/src/queue/lin_tests_dsl.ml
@@ -1,4 +1,4 @@
-module Queue_spec : Lin_base.ApiSpec = struct
+module Queue_spec : Lin_base.InterfaceSpec = struct
   open Lin_base
     type t = int Queue.t
     let init () = Queue.create ()
diff --git a/src/stack/lin_tests_dsl.ml b/src/stack/lin_tests_dsl.ml
index 4c0aac41f..84cc3daa3 100644
--- a/src/stack/lin_tests_dsl.ml
+++ b/src/stack/lin_tests_dsl.ml
@@ -1,4 +1,4 @@
-module Stack_spec : Lin_base.ApiSpec = struct
+module Stack_spec : Lin_base.InterfaceSpec = struct
     open Lin_base
     type t = int Stack.t
     let init () = Stack.create ()