diff --git a/lib/bcoin.js b/lib/bcoin.js
index 1a94b8ae..6f1573f4 100644
--- a/lib/bcoin.js
+++ b/lib/bcoin.js
@@ -134,10 +134,12 @@ const bcoin = exports;
 
 bcoin.define = function define(name, path) {
   let cache;
-  bcoin.__defineGetter__(name, function() {
-    if (!cache)
-      cache = require(path);
-    return cache;
+  Object.defineProperty(bcoin, name, {
+    get() {
+      if (!cache)
+        cache = require(path);
+      return cache;
+    }
   });
 };
 
diff --git a/lib/net/tcp.js b/lib/net/tcp.js
index 6c112654..2866e553 100644
--- a/lib/net/tcp.js
+++ b/lib/net/tcp.js
@@ -61,13 +61,14 @@ tcp.createServer = function createServer() {
     return server.address();
   };
 
-  ee.__defineGetter__('maxConnections', function() {
-    return server.maxConnections;
-  });
-
-  ee.__defineSetter__('maxConnections', function(value) {
-    server.maxConnections = value;
-    return server.maxConnections;
+  Object.defineProperty(ee, 'maxConnections', {
+    get() {
+      return server.maxConnections;
+    },
+    set(value) {
+      server.maxConnections = value;
+      return server.maxConnections;
+    }
   });
 
   server.on('listening', () => {
diff --git a/lib/script/script.js b/lib/script/script.js
index 47657aa7..833a7deb 100644
--- a/lib/script/script.js
+++ b/lib/script/script.js
@@ -104,30 +104,18 @@ Script.types = common.types;
 
 Script.typesByVal = common.typesByVal;
 
-/**
- * Getter to retrieve code length.
- * @name module:script.Script#length_getter
- * @method
- * @private
- * @returns {Number}
+/*
+ * Expose length setter and getter.
  */
 
-Script.prototype.__defineGetter__('length', function() {
-  return this.code.length;
-});
-
-/**
- * Setter to set code length.
- * @name module:script.Script#length_setter
- * @method
- * @private
- * @param {Number} value
- * @returns {Number}
- */
-
-Script.prototype.__defineSetter__('length', function(length) {
-  this.code.length = length;
-  return length;
+Object.defineProperty(Script.prototype, 'length', {
+  get() {
+    return this.code.length;
+  },
+  set(length) {
+    this.code.length = length;
+    return this.code.length;
+  }
 });
 
 /**
diff --git a/lib/script/stack.js b/lib/script/stack.js
index 22f6a87d..74f59f91 100644
--- a/lib/script/stack.js
+++ b/lib/script/stack.js
@@ -25,30 +25,18 @@ function Stack(items) {
   this.items = items || [];
 }
 
-/**
- * Getter to retrieve stack items length.
- * @name module:script.Stack#length_getter
- * @method
- * @private
- * @returns {Number}
+/*
+ * Expose length setter and getter.
  */
 
-Stack.prototype.__defineGetter__('length', function() {
-  return this.items.length;
-});
-
-/**
- * Setter to set stack items length.
- * @name module:script.Stack#length_setter
- * @method
- * @private
- * @param {Number} value
- * @returns {Number}
- */
-
-Stack.prototype.__defineSetter__('length', function(length) {
-  this.items.length = length;
-  return length;
+Object.defineProperty(Stack.prototype, 'length', {
+  get() {
+    return this.items.length;
+  },
+  set(length) {
+    this.items.length = length;
+    return this.items.length;
+  }
 });
 
 /**
diff --git a/lib/script/witness.js b/lib/script/witness.js
index 41cb4bd6..4ed7d19a 100644
--- a/lib/script/witness.js
+++ b/lib/script/witness.js
@@ -44,30 +44,18 @@ function Witness(options) {
     this.fromOptions(options);
 }
 
-/**
- * Getter to retrieve witness vector length.
- * @name module:script.Witness#length_getter
- * @method
- * @private
- * @returns {Number}
+/*
+ * Expose length setter and getter.
  */
 
-Witness.prototype.__defineGetter__('length', function() {
-  return this.items.length;
-});
-
-/**
- * Setter to set witness vector length.
- * @name module:script.Witness#length_setter
- * @method
- * @private
- * @param {Number} value
- * @returns {Number}
- */
-
-Witness.prototype.__defineSetter__('length', function(length) {
-  this.items.length = length;
-  return length;
+Object.defineProperty(Witness.prototype, 'length', {
+  get() {
+    return this.items.length;
+  },
+  set(length) {
+    this.items.length = length;
+    return this.items.length;
+  }
 });
 
 /**