diff --git a/contrib/03.callcc/callcc.c b/contrib/03.callcc/callcc.c
index e6750347..4020849c 100644
--- a/contrib/03.callcc/callcc.c
+++ b/contrib/03.callcc/callcc.c
@@ -66,8 +66,8 @@ cont_mark(pic_state *pic, void *data, void (*mark)(pic_state *, pic_value))
 
   /* callinfo */
   for (ci = cont->ci_ptr + cont->ci_offset; ci != cont->ci_ptr; --ci) {
-    if (ci->env) {
-      mark(pic, pic_obj_value(ci->env));
+    if (ci->cxt) {
+      mark(pic, pic_obj_value(ci->cxt));
     }
   }
 
diff --git a/extlib/benz/gc.c b/extlib/benz/gc.c
index 9a3c4c25..6f314178 100644
--- a/extlib/benz/gc.c
+++ b/extlib/benz/gc.c
@@ -354,22 +354,22 @@ gc_mark_object(pic_state *pic, struct pic_object *obj)
     gc_mark(pic, ((struct pic_pair *)obj)->cdr);
     break;
   }
-  case PIC_TT_ENV: {
-    struct pic_env *env = (struct pic_env *)obj;
+  case PIC_TT_CXT: {
+    struct pic_context *cxt = (struct pic_context *)obj;
     int i;
 
-    for (i = 0; i < env->regc; ++i) {
-      gc_mark(pic, env->regs[i]);
+    for (i = 0; i < cxt->regc; ++i) {
+      gc_mark(pic, cxt->regs[i]);
     }
-    if (env->up) {
-      gc_mark_object(pic, (struct pic_object *)env->up);
+    if (cxt->up) {
+      gc_mark_object(pic, (struct pic_object *)cxt->up);
     }
     break;
   }
   case PIC_TT_PROC: {
     struct pic_proc *proc = (struct pic_proc *)obj;
-    if (proc->env) {
-      gc_mark_object(pic, (struct pic_object *)proc->env);
+    if (proc->cxt) {
+      gc_mark_object(pic, (struct pic_object *)proc->cxt);
     }
     if (pic_proc_irep_p(proc)) {
       gc_mark_object(pic, (struct pic_object *)proc->u.irep);
@@ -542,8 +542,8 @@ gc_mark_phase(pic_state *pic)
 
   /* callinfo */
   for (ci = pic->ci; ci != pic->cibase; --ci) {
-    if (ci->env) {
-      gc_mark_object(pic, (struct pic_object *)ci->env);
+    if (ci->cxt) {
+      gc_mark_object(pic, (struct pic_object *)ci->cxt);
     }
   }
 
@@ -619,7 +619,7 @@ gc_finalize_object(pic_state *pic, struct pic_object *obj)
   case PIC_TT_PAIR: {
     break;
   }
-  case PIC_TT_ENV: {
+  case PIC_TT_CXT: {
     break;
   }
   case PIC_TT_PROC: {
diff --git a/extlib/benz/include/picrin.h b/extlib/benz/include/picrin.h
index 941935f9..84ab6f45 100644
--- a/extlib/benz/include/picrin.h
+++ b/extlib/benz/include/picrin.h
@@ -59,10 +59,10 @@ typedef struct {
   int argc, retc;
   pic_code *ip;
   pic_value *fp;
-  struct pic_env *env;
+  struct pic_context *cxt;
   int regc;
   pic_value *regs;
-  struct pic_env *up;
+  struct pic_context *up;
 } pic_callinfo;
 
 typedef void *(*pic_allocf)(void *, size_t);
diff --git a/extlib/benz/include/picrin/proc.h b/extlib/benz/include/picrin/proc.h
index edf128ae..472dfe8a 100644
--- a/extlib/benz/include/picrin/proc.h
+++ b/extlib/benz/include/picrin/proc.h
@@ -15,11 +15,11 @@ struct pic_func {
   pic_sym *name;
 };
 
-struct pic_env {
+struct pic_context {
   PIC_OBJECT_HEADER
   pic_value *regs;
   int regc;
-  struct pic_env *up;
+  struct pic_context *up;
   pic_value storage[1];
 };
 
@@ -30,7 +30,7 @@ struct pic_proc {
     struct pic_func func;
     struct pic_irep *irep;
   } u;
-  struct pic_env *env;
+  struct pic_context *cxt;
 };
 
 #define PIC_PROC_KIND_FUNC 1
@@ -42,11 +42,11 @@ struct pic_proc {
 #define pic_proc_p(o) (pic_type(o) == PIC_TT_PROC)
 #define pic_proc_ptr(o) ((struct pic_proc *)pic_ptr(o))
 
-#define pic_env_p(o) (pic_type(o) == PIC_TT_ENV)
-#define pic_env_ptr(o) ((struct pic_env *)pic_ptr(o))
+#define pic_context_p(o) (pic_type(o) == PIC_TT_CXT)
+#define pic_context_ptr(o) ((struct pic_context *)pic_ptr(o))
 
 struct pic_proc *pic_make_proc(pic_state *, pic_func_t, const char *);
-struct pic_proc *pic_make_proc_irep(pic_state *, struct pic_irep *, struct pic_env *);
+struct pic_proc *pic_make_proc_irep(pic_state *, struct pic_irep *, struct pic_context *);
 
 pic_sym *pic_proc_name(struct pic_proc *);
 
diff --git a/extlib/benz/include/picrin/value.h b/extlib/benz/include/picrin/value.h
index c821d06f..7f07ff4e 100644
--- a/extlib/benz/include/picrin/value.h
+++ b/extlib/benz/include/picrin/value.h
@@ -155,7 +155,7 @@ enum pic_tt {
   PIC_TT_PROC,
   PIC_TT_PORT,
   PIC_TT_ERROR,
-  PIC_TT_ENV,
+  PIC_TT_CXT,
   PIC_TT_SENV,
   PIC_TT_LIB,
   PIC_TT_IREP,
@@ -306,8 +306,8 @@ pic_type_repr(enum pic_tt tt)
     return "port";
   case PIC_TT_ERROR:
     return "error";
-  case PIC_TT_ENV:
-    return "env";
+  case PIC_TT_CXT:
+    return "cxt";
   case PIC_TT_PROC:
     return "proc";
   case PIC_TT_SENV:
diff --git a/extlib/benz/proc.c b/extlib/benz/proc.c
index 2f7d2d11..71b3195a 100644
--- a/extlib/benz/proc.c
+++ b/extlib/benz/proc.c
@@ -18,19 +18,19 @@ pic_make_proc(pic_state *pic, pic_func_t func, const char *name)
   proc->kind = PIC_PROC_KIND_FUNC;
   proc->u.func.f = func;
   proc->u.func.name = sym;
-  proc->env = NULL;
+  proc->cxt = NULL;
   return proc;
 }
 
 struct pic_proc *
-pic_make_proc_irep(pic_state *pic, struct pic_irep *irep, struct pic_env *env)
+pic_make_proc_irep(pic_state *pic, struct pic_irep *irep, struct pic_context *cxt)
 {
   struct pic_proc *proc;
 
   proc = (struct pic_proc *)pic_obj_alloc(pic, sizeof(struct pic_proc), PIC_TT_PROC);
   proc->kind = PIC_PROC_KIND_IREP;
   proc->u.irep = irep;
-  proc->env = env;
+  proc->cxt = cxt;
   return proc;
 }
 
diff --git a/extlib/benz/vm.c b/extlib/benz/vm.c
index 0daf0c72..9d26ee6b 100644
--- a/extlib/benz/vm.c
+++ b/extlib/benz/vm.c
@@ -473,33 +473,33 @@ pic_defvar(pic_state *pic, const char *name, pic_value init, struct pic_proc *co
 }
 
 static void
-vm_push_env(pic_state *pic)
+vm_push_cxt(pic_state *pic)
 {
   pic_callinfo *ci = pic->ci;
 
-  ci->env = (struct pic_env *)pic_obj_alloc(pic, sizeof(struct pic_env) + sizeof(pic_value) * (size_t)(ci->regc), PIC_TT_ENV);
-  ci->env->up = ci->up;
-  ci->env->regc = ci->regc;
-  ci->env->regs = ci->regs;
+  ci->cxt = (struct pic_context *)pic_obj_alloc(pic, sizeof(struct pic_context) + sizeof(pic_value) * (size_t)(ci->regc), PIC_TT_CXT);
+  ci->cxt->up = ci->up;
+  ci->cxt->regc = ci->regc;
+  ci->cxt->regs = ci->regs;
 }
 
 static void
 vm_tear_off(pic_callinfo *ci)
 {
-  struct pic_env *env;
+  struct pic_context *cxt;
   int i;
 
-  assert(ci->env != NULL);
+  assert(ci->cxt != NULL);
 
-  env = ci->env;
+  cxt = ci->cxt;
 
-  if (env->regs == env->storage) {
+  if (cxt->regs == cxt->storage) {
     return;                     /* is torn off */
   }
-  for (i = 0; i < env->regc; ++i) {
-    env->storage[i] = env->regs[i];
+  for (i = 0; i < cxt->regc; ++i) {
+    cxt->storage[i] = cxt->regs[i];
   }
-  env->regs = env->storage;
+  cxt->regs = cxt->storage;
 }
 
 void
@@ -508,7 +508,7 @@ pic_vm_tear_off(pic_state *pic)
   pic_callinfo *ci;
 
   for (ci = pic->ci; ci > pic->cibase; ci--) {
-    if (ci->env != NULL) {
+    if (ci->cxt != NULL) {
       vm_tear_off(ci);
     }
   }
@@ -764,10 +764,10 @@ pic_apply(pic_state *pic, struct pic_proc *proc, pic_value args)
       pic_callinfo *ci = pic->ci;
       struct pic_irep *irep;
 
-      if (ci->env != NULL && ci->env->regs == ci->env->storage) {
+      if (ci->cxt != NULL && ci->cxt->regs == ci->cxt->storage) {
         irep = pic_get_proc(pic)->u.irep;
         if (c.u.i >= irep->argc + irep->localc) {
-          PUSH(ci->env->regs[c.u.i - (ci->regs - ci->fp)]);
+          PUSH(ci->cxt->regs[c.u.i - (ci->regs - ci->fp)]);
           NEXT;
         }
       }
@@ -778,10 +778,10 @@ pic_apply(pic_state *pic, struct pic_proc *proc, pic_value args)
       pic_callinfo *ci = pic->ci;
       struct pic_irep *irep;
 
-      if (ci->env != NULL && ci->env->regs == ci->env->storage) {
+      if (ci->cxt != NULL && ci->cxt->regs == ci->cxt->storage) {
         irep = pic_get_proc(pic)->u.irep;
         if (c.u.i >= irep->argc + irep->localc) {
-          ci->env->regs[c.u.i - (ci->regs - ci->fp)] = POP();
+          ci->cxt->regs[c.u.i - (ci->regs - ci->fp)] = POP();
           NEXT;
         }
       }
@@ -790,24 +790,24 @@ pic_apply(pic_state *pic, struct pic_proc *proc, pic_value args)
     }
     CASE(OP_CREF) {
       int depth = c.u.r.depth;
-      struct pic_env *env;
+      struct pic_context *cxt;
 
-      env = pic->ci->up;
+      cxt = pic->ci->up;
       while (--depth) {
-	env = env->up;
+	cxt = cxt->up;
       }
-      PUSH(env->regs[c.u.r.idx]);
+      PUSH(cxt->regs[c.u.r.idx]);
       NEXT;
     }
     CASE(OP_CSET) {
       int depth = c.u.r.depth;
-      struct pic_env *env;
+      struct pic_context *cxt;
 
-      env = pic->ci->up;
+      cxt = pic->ci->up;
       while (--depth) {
-	env = env->up;
+	cxt = cxt->up;
       }
-      env->regs[c.u.r.idx] = POP();
+      cxt->regs[c.u.r.idx] = POP();
       NEXT;
     }
     CASE(OP_JMP) {
@@ -858,7 +858,7 @@ pic_apply(pic_state *pic, struct pic_proc *proc, pic_value args)
       ci->retc = 1;
       ci->ip = pic->ip;
       ci->fp = pic->sp - c.u.i;
-      ci->env = NULL;
+      ci->cxt = NULL;
       if (pic_proc_func_p(pic_proc_ptr(x))) {
 
         /* invoke! */
@@ -899,8 +899,8 @@ pic_apply(pic_state *pic, struct pic_proc *proc, pic_value args)
 	  }
 	}
 
-	/* prepare env */
-        ci->up = proc->env;
+	/* prepare cxt */
+        ci->up = proc->cxt;
         ci->regc = irep->capturec;
         ci->regs = ci->fp + irep->argc + irep->localc;
 
@@ -914,7 +914,7 @@ pic_apply(pic_state *pic, struct pic_proc *proc, pic_value args)
       pic_value *argv;
       pic_callinfo *ci;
 
-      if (pic->ci->env != NULL) {
+      if (pic->ci->cxt != NULL) {
         vm_tear_off(pic->ci);
       }
 
@@ -940,7 +940,7 @@ pic_apply(pic_state *pic, struct pic_proc *proc, pic_value args)
       pic_value *retv;
       pic_callinfo *ci;
 
-      if (pic->ci->env != NULL) {
+      if (pic->ci->cxt != NULL) {
         vm_tear_off(pic->ci);
       }
 
@@ -974,11 +974,11 @@ pic_apply(pic_state *pic, struct pic_proc *proc, pic_value args)
         pic_errorf(pic, "logic flaw");
       }
 
-      if (pic->ci->env == NULL) {
-        vm_push_env(pic);
+      if (pic->ci->cxt == NULL) {
+        vm_push_cxt(pic);
       }
 
-      proc = pic_make_proc_irep(pic, irep->irep[c.u.i], pic->ci->env);
+      proc = pic_make_proc_irep(pic, irep->irep[c.u.i], pic->ci->cxt);
       PUSH(pic_obj_value(proc));
       pic_gc_arena_restore(pic, ai);
       NEXT;