diff --git a/src/components/main/layout/block.rs b/src/components/main/layout/block.rs
index 7e3e89ae78d..607a85c2b7b 100644
--- a/src/components/main/layout/block.rs
+++ b/src/components/main/layout/block.rs
@@ -386,7 +386,7 @@ impl BlockFlow {
 
         let mut noncontent_height = Au::new(0);
         for box_ in self.box_.iter() {
-            let mut position = box_.position.get();
+            let mut position = box_.border_box.get();
             let mut margin = box_.margin.get();
 
             // The associated box is the border box of this flow.
@@ -421,7 +421,7 @@ impl BlockFlow {
 
             noncontent_height = noncontent_height + clearance + margin.top + margin.bottom;
 
-            box_.position.set(position);
+            box_.border_box.set(position);
             box_.margin.set(margin);
         }
 
@@ -450,7 +450,7 @@ impl BlockFlow {
         let mut margin_height = Au(0);
 
         for box_ in self.box_.iter() {
-            height = box_.position.get().size.height;
+            height = box_.border_box.get().size.height;
             clearance = match box_.clear() {
                 None => Au(0),
                 Some(clear) => self.base.floats_in.clearance(clear),
@@ -507,7 +507,7 @@ impl BlockFlow {
 
         let mut noncontent_height;
         let box_ = self.box_.as_ref().unwrap();
-        let mut position = box_.position.get();
+        let mut position = box_.border_box.get();
 
         // The associated box is the border box of this flow.
         position.origin.y = box_.margin.get().top;
@@ -523,7 +523,7 @@ impl BlockFlow {
         debug!("assign_height_float -- height: {}", height);
 
         position.size.height = height;
-        box_.position.set(position);
+        box_.border_box.set(position);
     }
 
     pub fn build_display_list_block<E:ExtraDisplayListData>(
@@ -756,7 +756,7 @@ impl Flow for BlockFlow {
             remaining_width = w;
 
             // The associated box is the border box of this flow.
-            let mut position_ref = box_.position.borrow_mut();
+            let mut position_ref = box_.border_box.borrow_mut();
             if self.is_fixed {
                 position_ref.get().origin.x = x_offset + box_.margin.get().left;
                 x_offset = x_offset + box_.padding.get().left;
diff --git a/src/components/main/layout/box_.rs b/src/components/main/layout/box_.rs
index 3f8f9183653..d4f16e1e37a 100644
--- a/src/components/main/layout/box_.rs
+++ b/src/components/main/layout/box_.rs
@@ -73,7 +73,7 @@ pub struct Box {
 
     /// The position of this box relative to its owning flow.
     /// The size includes padding and border, but not margin.
-    position: RefCell<Rect<Au>>,
+    border_box: RefCell<Rect<Au>>,
 
     /// The border of the content box.
     ///
@@ -386,7 +386,7 @@ impl Box {
         Box {
             node: OpaqueNode::from_thread_safe_layout_node(&node),
             style: node.style().clone(),
-            position: RefCell::new(Au::zero_rect()),
+            border_box: RefCell::new(Au::zero_rect()),
             border: RefCell::new(Zero::zero()),
             padding: RefCell::new(Zero::zero()),
             margin: RefCell::new(Zero::zero()),
@@ -405,7 +405,7 @@ impl Box {
         Box {
             node: node,
             style: style,
-            position: RefCell::new(Au::zero_rect()),
+            border_box: RefCell::new(Au::zero_rect()),
             border: RefCell::new(Zero::zero()),
             padding: RefCell::new(Zero::zero()),
             margin: RefCell::new(Zero::zero()),
@@ -502,7 +502,7 @@ impl Box {
         Box {
             node: self.node,
             style: self.style.clone(),
-            position: RefCell::new(Rect(self.position.get().origin, size)),
+            border_box: RefCell::new(Rect(self.border_box.get().origin, size)),
             border: RefCell::new(self.border.get()),
             padding: RefCell::new(self.padding.get()),
             margin: RefCell::new(self.margin.get()),
@@ -992,7 +992,7 @@ impl Box {
                               flow: &Flow,
                               index: uint,
                               lists: &RefCell<DisplayListCollection<E>>) {
-        let box_bounds = self.position.get();
+        let box_bounds = self.border_box.get();
         let absolute_box_bounds = box_bounds.translate(&offset);
         debug!("Box::build_display_list at rel={}, abs={}: {:s}",
                box_bounds, absolute_box_bounds, self.debug_str());
@@ -1395,7 +1395,7 @@ impl Box {
                 let left_box = if left_range.length() > 0 {
                     let new_text_box_info = ScannedTextBoxInfo::new(text_box_info.run.clone(), left_range);
                     let mut new_metrics = new_text_box_info.run.get().metrics_for_range(&left_range);
-                    new_metrics.bounding_box.size.height = self.position.get().size.height;
+                    new_metrics.bounding_box.size.height = self.border_box.get().size.height;
                     Some(self.transform(new_metrics.bounding_box.size,
                                         ScannedTextBox(new_text_box_info)))
                 } else {
@@ -1405,7 +1405,7 @@ impl Box {
                 let right_box = right_range.map_default(None, |range: Range| {
                     let new_text_box_info = ScannedTextBoxInfo::new(text_box_info.run.clone(), range);
                     let mut new_metrics = new_text_box_info.run.get().metrics_for_range(&range);
-                    new_metrics.bounding_box.size.height = self.position.get().size.height;
+                    new_metrics.bounding_box.size.height = self.border_box.get().size.height;
                     Some(self.transform(new_metrics.bounding_box.size,
                                         ScannedTextBox(new_text_box_info)))
                 });
@@ -1464,14 +1464,14 @@ impl Box {
                     }
                 };
 
-                let mut position = self.position.borrow_mut();
+                let mut position = self.border_box.borrow_mut();
                 position.get().size.width = width + self.noncontent_width() +
                     self.noncontent_inline_left() + self.noncontent_inline_right();
                 image_box_info.computed_width.set(Some(width));
             }
             ScannedTextBox(_) => {
                 // Scanned text boxes will have already had their content_widths assigned by this point.
-                let mut position = self.position.borrow_mut();
+                let mut position = self.border_box.borrow_mut();
                 position.get().size.width = position.get().size.width + self.noncontent_width() +
                     self.noncontent_inline_left() + self.noncontent_inline_right();
             }
@@ -1508,13 +1508,13 @@ impl Box {
                     }
                 };
 
-                let mut position = self.position.borrow_mut();
+                let mut position = self.border_box.borrow_mut();
                 image_box_info.computed_height.set(Some(height));
                 position.get().size.height = height + self.noncontent_height()
             }
             ScannedTextBox(_) => {
                 // Scanned text boxes will have already had their widths assigned by this point
-                let mut position = self.position.borrow_mut();
+                let mut position = self.border_box.borrow_mut();
                 position.get().size.height
                     = position.get().size.height + self.noncontent_height()
             }
@@ -1589,8 +1589,8 @@ impl Box {
             self.padding.get().left;
         let top = offset.y + self.margin.get().top + self.border.get().top +
             self.padding.get().top;
-        let width = self.position.get().size.width - self.noncontent_width();
-        let height = self.position.get().size.height - self.noncontent_height();
+        let width = self.border_box.get().size.width - self.noncontent_width();
+        let height = self.border_box.get().size.height - self.noncontent_height();
         let origin = Point2D(geometry::to_frac_px(left) as f32, geometry::to_frac_px(top) as f32);
         let size = Size2D(geometry::to_frac_px(width) as f32, geometry::to_frac_px(height) as f32);
         let rect = Rect(origin, size);
diff --git a/src/components/main/layout/flow.rs b/src/components/main/layout/flow.rs
index 2719885abb8..1cc1a1cf075 100644
--- a/src/components/main/layout/flow.rs
+++ b/src/components/main/layout/flow.rs
@@ -757,7 +757,7 @@ impl<'a> MutableFlowUtils for &'a mut Flow {
             let container_block_size = match self.class() {
                 BlockFlowClass => {
                     if self.as_block().box_.is_some() {
-                        self.as_block().box_.get_ref().position.get().size
+                        self.as_block().box_.get_ref().border_box.get().size
                     } else {
                         base(self).position.size
                     }
diff --git a/src/components/main/layout/inline.rs b/src/components/main/layout/inline.rs
index ee718001f43..8332c7adb7d 100644
--- a/src/components/main/layout/inline.rs
+++ b/src/components/main/layout/inline.rs
@@ -179,7 +179,7 @@ impl LineboxScanner {
                               -> (Rect<Au>, Au) {
         debug!("LineboxScanner: Trying to place first box of line {}", self.lines.len());
 
-        let first_box_size = first_box.position.get().size;
+        let first_box_size = first_box.border_box.get().size;
         let splittable = first_box.can_split();
         debug!("LineboxScanner: box size: {}, splittable: {}", first_box_size, splittable);
         let line_is_empty: bool = self.pending_line.range.length() == 0;
@@ -234,9 +234,9 @@ impl LineboxScanner {
 
                 debug!("LineboxScanner: case=box split and fit");
                 let actual_box_width = match (left, right) {
-                    (Some(l_box), Some(_))  => l_box.position.get().size.width,
-                    (Some(l_box), None)     => l_box.position.get().size.width,
-                    (None, Some(r_box))     => r_box.position.get().size.width,
+                    (Some(l_box), Some(_))  => l_box.border_box.get().size.width,
+                    (Some(l_box), None)     => l_box.border_box.get().size.width,
+                    (None, Some(r_box))     => r_box.border_box.get().size.width,
                     (None, None)            => fail!("This case makes no sense.")
                 };
                 return (line_bounds, actual_box_width);
@@ -248,9 +248,9 @@ impl LineboxScanner {
 
                 debug!("LineboxScanner: case=box split and fit didn't fit; trying to push it down");
                 let actual_box_width = match (left, right) {
-                    (Some(l_box), Some(_))  => l_box.position.get().size.width,
-                    (Some(l_box), None)     => l_box.position.get().size.width,
-                    (None, Some(r_box))     => r_box.position.get().size.width,
+                    (Some(l_box), Some(_))  => l_box.border_box.get().size.width,
+                    (Some(l_box), None)     => l_box.border_box.get().size.width,
+                    (None, Some(r_box))     => r_box.border_box.get().size.width,
                     (None, None)            => fail!("This case makes no sense.")
                 };
 
@@ -349,7 +349,7 @@ impl LineboxScanner {
         debug!("LineboxScanner: Trying to append box to line {:u} (box size: {}, green zone: \
                 {}): {:s}",
                self.lines.len(),
-               in_box.position.get().size,
+               in_box.border_box.get().size,
                self.pending_line.green_zone,
                in_box.debug_str());
 
@@ -369,7 +369,7 @@ impl LineboxScanner {
         // horizontally. We'll try to place the whole box on this line and break somewhere if it
         // doesn't fit.
 
-        let new_width = self.pending_line.bounds.size.width + in_box.position.get().size.width;
+        let new_width = self.pending_line.bounds.size.width + in_box.border_box.get().size.width;
         if new_width <= green_zone.width {
             debug!("LineboxScanner: case=box fits without splitting");
             self.push_box_to_line(in_box);
@@ -440,9 +440,9 @@ impl LineboxScanner {
         }
         self.pending_line.range.extend_by(1);
         self.pending_line.bounds.size.width = self.pending_line.bounds.size.width +
-            box_.position.get().size.width;
+            box_.border_box.get().size.width;
         self.pending_line.bounds.size.height = Au::max(self.pending_line.bounds.size.height,
-                                                       box_.position.get().size.height);
+                                                       box_.border_box.get().size.height);
         self.new_boxes.push(box_);
     }
 }
@@ -603,8 +603,8 @@ impl InlineFlow {
 
         for i in line.range.eachi() {
             let box_ = &boxes[i];
-            let size = box_.position.get().size;
-            box_.position.set(Rect(Point2D(offset_x, box_.position.get().origin.y), size));
+            let size = box_.border_box.get().size;
+            box_.border_box.set(Rect(Point2D(offset_x, box_.border_box.get().origin.y), size));
             offset_x = offset_x + size.width;
         }
     }
@@ -764,12 +764,12 @@ impl Flow for InlineFlow {
 
                         // Offset from the top of the box is 1/2 of the leading + ascent
                         let text_offset = text_ascent + (line_height - em_size).scale_by(0.5);
-                        text_bounds.translate(&Point2D(cur_box.position.get().origin.x, Au(0)));
+                        text_bounds.translate(&Point2D(cur_box.border_box.get().origin.x, Au(0)));
 
                         (text_offset, line_height - text_offset, text_ascent)
                     },
                     GenericBox | IframeBox(_) => {
-                        let height = cur_box.position.get().size.height;
+                        let height = cur_box.border_box.get().size.height;
                         (height, Au::new(0), height)
                     },
                     UnscannedTextBox(_) => {
@@ -824,7 +824,7 @@ impl Flow for InlineFlow {
                     bottommost = bottom_from_base;
                 }
 
-                cur_box.position.borrow_mut().get().origin.y = line.bounds.origin.y + offset + top;
+                cur_box.border_box.borrow_mut().get().origin.y = line.bounds.origin.y + offset + top;
             }
 
             // Calculate the distance from baseline to the top of the biggest box with 'bottom'
@@ -853,7 +853,7 @@ impl Flow for InlineFlow {
                     _ => baseline_offset,
                 };
 
-                cur_box.position.borrow_mut().get().origin.y = cur_box.position.get().origin.y +
+                cur_box.border_box.borrow_mut().get().origin.y = cur_box.border_box.get().origin.y +
                     adjust_offset;
 
                 if cur_box.inline_info.with(|info| info.is_none()) {