diff --git a/autoload/nerdtree.vim b/autoload/nerdtree.vim
index c8f96e7..6d7828d 100644
--- a/autoload/nerdtree.vim
+++ b/autoload/nerdtree.vim
@@ -11,10 +11,10 @@ endfunction
 "============================================================
 
 "FUNCTION: nerdtree#checkForBrowse(dir) {{{2
-"inits a secondary nerd tree in the current buffer if appropriate
+"inits a window tree in the current buffer if appropriate
 function! nerdtree#checkForBrowse(dir)
     if a:dir != '' && isdirectory(a:dir)
-        call g:NERDTreeCreator.CreateSecondary(a:dir)
+        call g:NERDTreeCreator.CreateWindowTree(a:dir)
     endif
 endfunction
 
diff --git a/autoload/nerdtree/ui_glue.vim b/autoload/nerdtree/ui_glue.vim
index dadb8f8..50298d2 100644
--- a/autoload/nerdtree/ui_glue.vim
+++ b/autoload/nerdtree/ui_glue.vim
@@ -208,7 +208,7 @@ endfunction
 " FUNCTION: s:closeTreeWindow() {{{1
 " close the tree window
 function! s:closeTreeWindow()
-    if b:NERDTreeType ==# "secondary" && b:NERDTreePreviousBuf != -1
+    if b:NERDTreeType ==# "window" && b:NERDTreePreviousBuf != -1
         exec "buffer " . b:NERDTreePreviousBuf
     else
         if winnr("$") > 1
@@ -269,14 +269,14 @@ function! s:findAndRevealPath()
         endtry
 
         if p.isUnder(cwd)
-            call g:NERDTreeCreator.CreatePrimary(cwd.str())
+            call g:NERDTreeCreator.CreateTabTree(cwd.str())
         else
-            call g:NERDTreeCreator.CreatePrimary(p.getParent().str())
+            call g:NERDTreeCreator.CreateTabTree(p.getParent().str())
         endif
     else
         if !p.isUnder(g:NERDTreeFileNode.GetRootForTab().path)
             if !g:NERDTree.IsOpen()
-                call g:NERDTreeCreator.TogglePrimary('')
+                call g:NERDTreeCreator.ToggleTabTree('')
             else
                 call g:NERDTree.CursorToTreeWin()
             endif
@@ -284,7 +284,7 @@ function! s:findAndRevealPath()
             call s:chRoot(g:NERDTreeDirNode.New(p.getParent()))
         else
             if !g:NERDTree.IsOpen()
-                call g:NERDTreeCreator.TogglePrimary("")
+                call g:NERDTreeCreator.ToggleTabTree("")
             endif
         endif
     endif
@@ -545,10 +545,10 @@ endfunction
 
 " FUNCTION: nerdtree#ui_glue#setupCommands() {{{1
 function! nerdtree#ui_glue#setupCommands()
-    command! -n=? -complete=dir -bar NERDTree :call g:NERDTreeCreator.CreatePrimary('<args>')
-    command! -n=? -complete=dir -bar NERDTreeToggle :call g:NERDTreeCreator.TogglePrimary('<args>')
+    command! -n=? -complete=dir -bar NERDTree :call g:NERDTreeCreator.CreateTabTree('<args>')
+    command! -n=? -complete=dir -bar NERDTreeToggle :call g:NERDTreeCreator.ToggleTabTree('<args>')
     command! -n=0 -bar NERDTreeClose :call g:NERDTree.Close()
-    command! -n=1 -complete=customlist,nerdtree#completeBookmarks -bar NERDTreeFromBookmark call g:NERDTreeCreator.CreatePrimary('<args>')
+    command! -n=1 -complete=customlist,nerdtree#completeBookmarks -bar NERDTreeFromBookmark call g:NERDTreeCreator.CreateTabTree('<args>')
     command! -n=0 -bar NERDTreeMirror call g:NERDTreeCreator.CreateMirror()
     command! -n=0 -bar NERDTreeFind call s:findAndRevealPath()
     command! -n=0 -bar NERDTreeFocus call NERDTreeFocus()
diff --git a/doc/NERD_tree.txt b/doc/NERD_tree.txt
index 963c6c2..caab120 100644
--- a/doc/NERD_tree.txt
+++ b/doc/NERD_tree.txt
@@ -776,13 +776,13 @@ Default: 1.
 If set to 1, doing a >
     :edit <some directory>
 <
-will open up a "secondary" NERD tree instead of a netrw in the target window.
+will open up a window level NERD tree instead of a netrw in the target window.
 
-Secondary NERD trees behaves slightly different from a regular trees in the
+Window level trees behaves slightly different from a regular trees in the
 following respects:
     1. 'o' will open the selected file in the same window as the tree,
        replacing it.
-    2. you can have as many secondary tree as you want in the same tab.
+    2. you can have one tree per window - instead of per tab.
 
 ------------------------------------------------------------------------------
                                                             *'NERDTreeIgnore'*
diff --git a/lib/nerdtree/creator.vim b/lib/nerdtree/creator.vim
index 89f03a3..842311c 100644
--- a/lib/nerdtree/creator.vim
+++ b/lib/nerdtree/creator.vim
@@ -1,5 +1,5 @@
 "CLASS: Creator
-"Creates primary/secondary/mirror nerdtree windows. Sets up all the window and
+"Creates tab/window/mirror nerdtree windows. Sets up all the window and
 "buffer options and key mappings etc.
 "============================================================
 let s:Creator = {}
@@ -32,15 +32,15 @@ function! s:Creator.BufNamePrefix()
     return 'NERD_tree_'
 endfunction
 
-"FUNCTION: s:Creator.CreatePrimary(a:name) {{{1
-function! s:Creator.CreatePrimary(name)
+"FUNCTION: s:Creator.CreateTabTree(a:name) {{{1
+function! s:Creator.CreateTabTree(name)
     let creator = s:Creator.New()
-    call creator.createPrimary(a:name)
+    call creator.createTabTree(a:name)
 endfunction
 
-"FUNCTION: s:Creator.createPrimary(a:name) {{{1
+"FUNCTION: s:Creator.createTabTree(a:name) {{{1
 "name: the name of a bookmark or a directory
-function! s:Creator.createPrimary(name)
+function! s:Creator.createTabTree(name)
     let path = self._pathForString(a:name)
     
     "abort if exception was thrown (bookmark/dir doesn't exist)
@@ -67,7 +67,7 @@ function! s:Creator.createPrimary(name)
 
     call self._createTreeWin()
     call self._createNERDTree(path)
-    let b:NERDTreeType = "primary"
+    let b:NERDTreeType = "tab"
     let b:treeShowHelp = 0
     let b:NERDTreeIgnoreEnabled = 1
     let b:NERDTreeShowFiles = g:NERDTreeShowFiles
@@ -80,14 +80,14 @@ function! s:Creator.createPrimary(name)
     call self._broadcastInitEvent()
 endfunction
 
-"FUNCTION: s:Creator.CreateSecondary(dir) {{{1
-function! s:Creator.CreateSecondary(dir)
+"FUNCTION: s:Creator.CreateWindowTree(dir) {{{1
+function! s:Creator.CreateWindowTree(dir)
     let creator = s:Creator.New()
-    call creator.createSecondary(a:dir)
+    call creator.createWindowTree(a:dir)
 endfunction
 
-"FUNCTION: s:Creator.createSecondary(dir) {{{1
-function! s:Creator.createSecondary(dir)
+"FUNCTION: s:Creator.createWindowTree(dir) {{{1
+function! s:Creator.createWindowTree(dir)
     try
         let path = g:NERDTreePath.New(a:dir)
     catch /^NERDTree.InvalidArgumentsError/
@@ -100,14 +100,14 @@ function! s:Creator.createSecondary(dir)
 
     let previousBuf = expand("#")
 
-    "we need a unique name for each secondary tree buffer to ensure they are
+    "we need a unique name for each window tree buffer to ensure they are
     "all independent
     exec "silent edit " . self._nextBufferName()
 
     let b:NERDTreePreviousBuf = bufnr(previousBuf)
     call self._createNERDTree(path)
     call self._setCommonBufOptions()
-    let b:NERDTreeType = "secondary"
+    let b:NERDTreeType = "window"
 
     call b:NERDTree.render()
 
@@ -322,20 +322,20 @@ function! s:Creator._tabpagevar(tabnr, var)
     return v
 endfunction
 
-"FUNCTION: s:Creator.TogglePrimary(dir) {{{1
-function! s:Creator.TogglePrimary(dir)
+"FUNCTION: s:Creator.ToggleTabTree(dir) {{{1
+function! s:Creator.ToggleTabTree(dir)
     let creator = s:Creator.New()
-    call creator.togglePrimary(a:dir)
+    call creator.toggleTabTree(a:dir)
 endfunction
 
-"FUNCTION: s:Creator.togglePrimary(dir) {{{1
+"FUNCTION: s:Creator.toggleTabTree(dir) {{{1
 "Toggles the NERD tree. I.e the NERD tree is open, it is closed, if it is
 "closed it is restored or initialized (if it doesnt exist)
 "
 "Args:
 "dir: the full path for the root node (is only used if the NERD tree is being
 "initialized.
-function! s:Creator.togglePrimary(dir)
+function! s:Creator.toggleTabTree(dir)
     if g:NERDTree.ExistsForTab()
         if !g:NERDTree.IsOpen()
             call self._createTreeWin()
@@ -347,7 +347,7 @@ function! s:Creator.togglePrimary(dir)
             call g:NERDTree.Close()
         endif
     else
-        call self.createPrimary(a:dir)
+        call self.createTabTree(a:dir)
     endif
 endfunction
 
diff --git a/lib/nerdtree/nerdtree.vim b/lib/nerdtree/nerdtree.vim
index 55f3dd7..46e7129 100644
--- a/lib/nerdtree/nerdtree.vim
+++ b/lib/nerdtree/nerdtree.vim
@@ -9,7 +9,7 @@ function! s:NERDTree.AddPathFilter(callback)
 endfunction
 
 "FUNCTION: s:NERDTree.Close() {{{1
-"Closes the primary NERD tree window for this tab
+"Closes the tab tree window for this tab
 function! s:NERDTree.Close()
     if !s:NERDTree.IsOpen()
         return
diff --git a/lib/nerdtree/opener.vim b/lib/nerdtree/opener.vim
index 3a6b392..6740bd4 100644
--- a/lib/nerdtree/opener.vim
+++ b/lib/nerdtree/opener.vim
@@ -64,7 +64,7 @@ endfunction
 
 "FUNCTION: Opener._gotoTargetWin() {{{1
 function! s:Opener._gotoTargetWin()
-    if b:NERDTreeType ==# "secondary"
+    if b:NERDTreeType ==# "window"
         if self._where == 'v'
             vsplit
         elseif self._where == 'h'
@@ -248,7 +248,7 @@ function! s:Opener._openFile()
 
     call self._gotoTargetWin()
 
-    if self._treetype ==# "secondary"
+    if self._treetype ==# "window"
         call self._path.edit()
     else
         call self._path.edit()
@@ -262,9 +262,9 @@ endfunction
 
 "FUNCTION: Opener._openDirectory(node) {{{1
 function! s:Opener._openDirectory(node)
-    if self._treetype ==# "secondary"
+    if self._treetype ==# "window"
         call self._gotoTargetWin()
-        call g:NERDTreeCreator.CreateSecondary(a:node.path.str())
+        call g:NERDTreeCreator.CreateWindow(a:node.path.str())
     else
         call self._gotoTargetWin()
         if empty(self._where)
@@ -272,9 +272,9 @@ function! s:Opener._openDirectory(node)
             call b:NERDTree.render()
             call a:node.putCursorHere(0, 0)
         elseif self._where == 't'
-            call g:NERDTreeCreator.CreatePrimary(a:node.path.str())
+            call g:NERDTreeCreator.CreateTabTree(a:node.path.str())
         else
-            call g:NERDTreeCreator.CreateSecondary(a:node.path.str())
+            call g:NERDTreeCreator.CreateWindow(a:node.path.str())
         endif
     endif
 
diff --git a/lib/nerdtree/tree_dir_node.vim b/lib/nerdtree/tree_dir_node.vim
index a1e4214..c7c016c 100644
--- a/lib/nerdtree/tree_dir_node.vim
+++ b/lib/nerdtree/tree_dir_node.vim
@@ -352,7 +352,7 @@ endfunction
 "FUNCTION: TreeDirNode._openInNewTab() {{{1
 function! s:TreeDirNode._openInNewTab()
     tabnew
-    call g:NERDTreeCreator.CreatePrimary(self.path.str())
+    call g:NERDTreeCreator.CreateTabTree(self.path.str())
 endfunction
 
 "FUNCTION: TreeDirNode.openRecursively() {{{1
diff --git a/lib/nerdtree/ui.vim b/lib/nerdtree/ui.vim
index 74cee9c..1e18858 100644
--- a/lib/nerdtree/ui.vim
+++ b/lib/nerdtree/ui.vim
@@ -27,12 +27,12 @@ function! s:UI._dumpHelp()
         let @h=@h."\" File node mappings~\n"
         let @h=@h."\" ". (g:NERDTreeMouseMode ==# 3 ? "single" : "double") ."-click,\n"
         let @h=@h."\" <CR>,\n"
-        if b:NERDTreeType ==# "primary"
+        if b:NERDTreeType ==# "tab"
             let @h=@h."\" ". g:NERDTreeMapActivateNode .": open in prev window\n"
         else
             let @h=@h."\" ". g:NERDTreeMapActivateNode .": open in current window\n"
         endif
-        if b:NERDTreeType ==# "primary"
+        if b:NERDTreeType ==# "tab"
             let @h=@h."\" ". g:NERDTreeMapPreview .": preview\n"
         endif
         let @h=@h."\" ". g:NERDTreeMapOpenInTab.": open in new tab\n"
diff --git a/plugin/NERD_tree.vim b/plugin/NERD_tree.vim
index 8494a09..42a3b1e 100644
--- a/plugin/NERD_tree.vim
+++ b/plugin/NERD_tree.vim
@@ -188,7 +188,7 @@ function! NERDTreeFocus()
     if g:NERDTree.IsOpen()
         call g:NERDTree.CursorToTreeWin()
     else
-        call g:NERDTreeCreator.TogglePrimary("")
+        call g:NERDTreeCreator.ToggleTabTree("")
     endif
 endfunction