diff --git a/src/librustc_mir/interpret/operand.rs b/src/librustc_mir/interpret/operand.rs
index 2ec1613bce2..9e94ae2c160 100644
--- a/src/librustc_mir/interpret/operand.rs
+++ b/src/librustc_mir/interpret/operand.rs
@@ -24,7 +24,7 @@ use rustc_macros::HashStable;
 ///
 /// For optimization of a few very common cases, there is also a representation for a pair of
 /// primitive values (`ScalarPair`). It allows Miri to avoid making allocations for checked binary
-/// operations and fat pointers. This idea was taken from rustc's codegen.
+/// operations and wide pointers. This idea was taken from rustc's codegen.
 /// In particular, thanks to `ScalarPair`, arithmetic operations and casts can be entirely
 /// defined on `Immediate`, and do not have to work with a `Place`.
 #[derive(Copy, Clone, Debug, PartialEq, Eq, HashStable, Hash)]
@@ -74,7 +74,7 @@ impl<'tcx, Tag> Immediate<Tag> {
     pub fn to_scalar_or_undef(self) -> ScalarMaybeUndef<Tag> {
         match self {
             Immediate::Scalar(val) => val,
-            Immediate::ScalarPair(..) => bug!("Got a fat pointer where a scalar was expected"),
+            Immediate::ScalarPair(..) => bug!("Got a wide pointer where a scalar was expected"),
         }
     }
 
@@ -331,7 +331,7 @@ impl<'mir, 'tcx, M: Machine<'mir, 'tcx>> InterpCx<'mir, 'tcx, M> {
         Ok(self.read_immediate(op)?.to_scalar_or_undef())
     }
 
-    // Turn the fat MPlace into a string (must already be dereferenced!)
+    // Turn the wide MPlace into a string (must already be dereferenced!)
     pub fn read_str(
         &self,
         mplace: MPlaceTy<'tcx, M::PointerTag>,
diff --git a/src/librustc_mir/interpret/place.rs b/src/librustc_mir/interpret/place.rs
index ea7b53b3dda..8da20a4bba2 100644
--- a/src/librustc_mir/interpret/place.rs
+++ b/src/librustc_mir/interpret/place.rs
@@ -125,7 +125,7 @@ impl<Tag> MemPlace<Tag> {
         Self::from_scalar_ptr(ptr.into(), align)
     }
 
-    /// Turn a mplace into a (thin or fat) pointer, as a reference, pointing to the same space.
+    /// Turn a mplace into a (thin or wide) pointer, as a reference, pointing to the same space.
     /// This is the inverse of `ref_to_mplace`.
     #[inline(always)]
     pub fn to_ref(self) -> Immediate<Tag> {
@@ -278,7 +278,7 @@ where
     M::MemoryMap: AllocMap<AllocId, (MemoryKind<M::MemoryKinds>, Allocation<Tag, M::AllocExtra>)>,
     M::AllocExtra: AllocationExtra<Tag>,
 {
-    /// Take a value, which represents a (thin or fat) reference, and make it a place.
+    /// Take a value, which represents a (thin or wide) reference, and make it a place.
     /// Alignment is just based on the type.  This is the inverse of `MemPlace::to_ref()`.
     ///
     /// Only call this if you are sure the place is "valid" (aligned and inbounds), or do not
@@ -1034,7 +1034,7 @@ where
         MPlaceTy::from_aligned_ptr(ptr, layout)
     }
 
-    /// Returns a fat MPlace.
+    /// Returns a wide MPlace.
     pub fn allocate_str(
         &mut self,
         str: &str,