--- a/docs/tutorial/slides.md	Sat Apr 27 21:09:47 2019 -0400
+++ b/docs/tutorial/slides.md	Sat Apr 27 21:24:18 2019 -0400
@@ -852,7 +852,7 @@
 output/edit-mid-stack.log
 ```
 
-The message `1 new orphan changesets` means that, by amending a changeset having a child, this child is now **unstable**, as we can see with the `hg stack` command:
+The message `1 new orphan changesets` means that, by amending a changeset having a child, this child is now **orphan**, as we can see with the `hg stack` command:
 
 ```raw-file
 output/edit-mid-stack-after-stack.log
@@ -909,7 +909,7 @@
 output/basic-stabilize-before-log-obsolete.log
 ```
 
-A changeset can also be **unstable**, meaning that it could be subject to one or more **instabilities**:
+A changeset can also be **orphan**, meaning that it could be subject to one or more **instabilities**:
 
 * **orphan**, a changeset whose an ancestor is **obsolete**.
 * **content-divergent**, a changeset which has been rewritten in two different versions.
@@ -1501,7 +1501,7 @@
 $> hg update --rev t1
 1 files updated, 0 files merged, 0 files removed, 0 files unresolved
 $> hg commit --amend -m "Step1"
-<span style="color:gold;">3 new unstable changesets</span>
+<span style="color:gold;">3 new orphan changesets</span>
 </pre>
 
 #### What have we done?
@@ -1510,11 +1510,11 @@
 $> hg log -G -T compact
 @  <span style="color:olive;">9</span>[tip]     1aa1be5ada40    Step1
 |
-| o  <span style="color:olive;">8</span>        cf90b2de7e65    Step4 <span style="color:red;">(unstable)</span>
+| o  <span style="color:olive;">8</span>        cf90b2de7e65    Step4 <span style="color:red;">(orphan)</span>
 | |
-| o  <span style="color:olive;">7</span>        e208d4205c8e    Step3 <span style="color:red;">(unstable)</span>
+| o  <span style="color:olive;">7</span>        e208d4205c8e    Step3 <span style="color:red;">(orphan)</span>
 | |
-| o  <span style="color:olive;">6</span>        673ff300cf3a    Step2 <span style="color:red;">(unstable)</span>
+| o  <span style="color:olive;">6</span>        673ff300cf3a    Step2 <span style="color:red;">(orphan)</span>
 | |
 | <span style="color:grey;">x  5        8bb88a31dd28    Step</span>
 |/
@@ -1528,9 +1528,9 @@
 $> hg stack
 ###### topic: <span style="color:green;">myfeature</span>
 ###### branch: feature
-<span style="color:olive;">t4</span><span style="color:red;">$</span> Step4<span style="color:red;"> (unstable)</span>
-<span style="color:olive;">t3</span><span style="color:red;">$</span> Step3<span style="color:red;"> (unstable)</span>
-<span style="color:olive;">t2</span><span style="color:red;">$</span> Step2<span style="color:red;"> (unstable)</span>
+<span style="color:olive;">t4</span><span style="color:red;">$</span> Step4<span style="color:red;"> (orphan)</span>
+<span style="color:olive;">t3</span><span style="color:red;">$</span> Step3<span style="color:red;"> (orphan)</span>
+<span style="color:olive;">t2</span><span style="color:red;">$</span> Step2<span style="color:red;"> (orphan)</span>
 <span style="color:teal;">t1</span><span style="color:teal;font-weight:bold;">@</span> <span style="color:teal;">Step1</span><span style="color:teal;font-weight:bold;"> (current)</span>
 <span style="color:grey;">t0^ Trunk</span>
 </pre>
@@ -1545,8 +1545,8 @@
 $> hg stack
 ###### topic: <span style="color:green;">myfeature</span>
 ###### branch: feature
-<span style="color:olive;">t4</span><span style="color:red;">$</span> Step4<span style="color:red;"> (unstable)</span>
-<span style="color:olive;">t3</span><span style="color:red;">$</span> Step3<span style="color:red;"> (unstable)</span>
+<span style="color:olive;">t4</span><span style="color:red;">$</span> Step4<span style="color:red;"> (orphan)</span>
+<span style="color:olive;">t3</span><span style="color:red;">$</span> Step3<span style="color:red;"> (orphan)</span>
 <span style="color:teal;">t2</span><span style="color:teal;font-weight:bold;">@</span> <span style="color:teal;">Step2</span><span style="color:teal;font-weight:bold;"> (current)</span>
 <span style="color:olive;">t1</span><span style="color:green;">:</span> Step1
 <span style="color:grey;">t0^ Trunk</span>
@@ -1566,7 +1566,7 @@
 $> hg stack
 ###### topic: <span style="color:green;">myfeature</span>
 ###### branch: feature
-<span style="color:olive;">t4</span><span style="color:red;">$</span> Step4<span style="color:red;"> (unstable)</span>
+<span style="color:olive;">t4</span><span style="color:red;">$</span> Step4<span style="color:red;"> (orphan)</span>
 <span style="color:teal;">t3</span><span style="color:teal;font-weight:bold;">@</span> <span style="color:teal;">Step3</span><span style="color:teal;font-weight:bold;"> (current)</span>
 <span style="color:olive;">t2</span><span style="color:green;">:</span> Step2
 <span style="color:olive;">t1</span><span style="color:green;">:</span> Step1
@@ -1838,13 +1838,13 @@
 
 <pre>
 $> hg summary
-<span style="color:olive;">parent: 10:890ac95deb83 </span>tip (unstable)
+<span style="color:olive;">parent: 10:890ac95deb83 </span>tip (orphan)
  Head
 branch: feature
 commit: (clean)
 update: (current)
 phases: 9 draft
-unstable: <span style="color:red;">1 changesets</span>
+orphan: <span style="color:red;">1 changesets</span>
 topic:  <span style="color:green;">myfeature</span>
 </pre>
 
@@ -1864,7 +1864,7 @@
    packaging
    prev-next
    split
-   stack_unstable_bug
+   stack_orphan_bug
    tutorial
  * tutorialtypos
 </pre>
@@ -1883,7 +1883,7 @@
    obscache               (2 months ago)
    evolvecolor            (2 months ago)
    obsrangecacheiterative (2 months ago)
-   stack_unstable_bug     (2 months ago)
+   stack_orphan_bug     (2 months ago)
    doc                    (3 months ago)
    split                  (3 months ago)
    import-checker         (4 months ago)
@@ -1906,7 +1906,7 @@
    packaging              (on branch: default, 1 changesets, <span style="color:teal;">2521 behind</span>)
    prev-next              (on branch: default, 4 changesets, <span style="color:teal;">72 behind</span>)
    split                  (on branch: default, 1 changesets, <span style="color:teal;">492 behind</span>)
-   stack_unstable_bug     (on branch: default, 1 changesets, <span style="color:teal;">474 behind</span>)
+   stack_orphan_bug     (on branch: default, 1 changesets, <span style="color:teal;">474 behind</span>)
    tutorial               (on branch: default, 2 changesets, <span style="color:teal;">492 behind</span>)
 <span style="color:green;"> * </span><span style="color:green;">tutorialtypos         </span> (on branch: default, 3 changesets, <span style="color:red;">1 troubled</span>, <span style="color:olive;">2 heads</span>, <span style="color:teal;">2 behind</span>)
 </pre>
@@ -1919,7 +1919,7 @@
 |
 o  23abfc79b7ce
 |
-| o  4302274177b9 <span style="color:red;">(unstable)</span>
+| o  4302274177b9 <span style="color:red;">(orphan)</span>
 | |
 | <span style="color:grey;">x  fba593aaaa10</span>
 |/   rewritten as c55cb2ee8a91;
@@ -1931,10 +1931,10 @@
 <pre>
 $> hg evolve --list
 <span style="color:gold;">9ac0d376e01c</span>: changelog: introduce a 'tiprev' method
-  <span style="color:red;">unstable</span>: <span style="color:grey;">52ec3072fe46</span> (obsolete parent)
+  <span style="color:red;">orphan</span>: <span style="color:grey;">52ec3072fe46</span> (obsolete parent)
 
 <span style="color:gold;">3efd3eab9860</span>: changelog: use 'tiprev()' in 'tip()'
-  <span style="color:red;">unstable</span>: <span style="color:red;">9ac0d376e01c</span> (unstable parent)
+  <span style="color:red;">orphan</span>: <span style="color:red;">9ac0d376e01c</span> (orphan parent)
 </pre>
 
 (see also `hg evolve --list --rev`)
@@ -2033,7 +2033,7 @@
 
 * Hide **most** of the complexity
 
-* Help with unstable situations
+* Help with orphan situations
 
     - Automatic detection
 
@@ -2116,7 +2116,7 @@
     }
 ~~~
 
-#### Unstable
+#### Orphan
 
 Now called `orphan`
 
@@ -2129,14 +2129,14 @@
         node[group=main];
         Root -> New;
         node[group=obsolete];
-        Root -> Obsolete -> Unstable;
+        Root -> Obsolete -> Orphan;
 
         // Obsolescence links
         edge[dir=back, style=dotted, arrowtail=dot];
         Obsolete -> New;
 
         Obsolete [fillcolor="#DFDFFF"];
-        Unstable [fillcolor="#FF3535"];
+        Orphan [fillcolor="#FF3535"];
         Root[shape="circle"];
     }
 ~~~