diff --git a/BizHawk.Client.EmuHawk/tools/Debugger/Breakpoint.cs b/BizHawk.Client.EmuHawk/tools/Debugger/Breakpoint.cs
index f1f630a56a..3f4aca4106 100644
--- a/BizHawk.Client.EmuHawk/tools/Debugger/Breakpoint.cs
+++ b/BizHawk.Client.EmuHawk/tools/Debugger/Breakpoint.cs
@@ -9,9 +9,9 @@ namespace BizHawk.Client.EmuHawk
 	{
 		public Action Callback { get; set; }
 
-		public void Add(IDebuggable core, string domain, uint address, uint mask, MemoryCallbackType type)
+		public void Add(IDebuggable core, string scope, uint address, uint mask, MemoryCallbackType type)
 		{
-			Add(new Breakpoint(core, domain, Callback, address, mask, type));
+			Add(new Breakpoint(core, scope, Callback, address, mask, type));
 		}
 
 		public new void Clear()
@@ -69,9 +69,9 @@ namespace BizHawk.Client.EmuHawk
 		private bool _active;
 		private readonly IDebuggable _core;
 
-		public Breakpoint(bool readOnly, IDebuggable core, string domain, Action callBack, uint address, uint mask, MemoryCallbackType type, bool enabled = true)
+		public Breakpoint(bool readOnly, IDebuggable core, string scope, Action callBack, uint address, uint mask, MemoryCallbackType type, bool enabled = true)
 		{
-			Domain = domain;
+			Scope = scope;
 			_core = core;
 			Type = type;
 			Callback = callBack;
@@ -83,9 +83,9 @@ namespace BizHawk.Client.EmuHawk
 			ReadOnly = readOnly;
 		}
 
-		public Breakpoint(IDebuggable core, string domain, Action callBack, uint address, uint mask, MemoryCallbackType type, bool enabled = true)
+		public Breakpoint(IDebuggable core, string scope, Action callBack, uint address, uint mask, MemoryCallbackType type, bool enabled = true)
 		{
-			Domain = domain;
+			Scope = scope;
 			_core = core;
 			Type = type;
 			Callback = callBack;
@@ -96,9 +96,9 @@ namespace BizHawk.Client.EmuHawk
 			Active = enabled;
 		}
 
-		public Breakpoint(string name, bool readOnly, IDebuggable core, string domain, Action callBack, uint address, uint mask, MemoryCallbackType type, bool enabled = true)
+		public Breakpoint(string name, bool readOnly, IDebuggable core, string scope, Action callBack, uint address, uint mask, MemoryCallbackType type, bool enabled = true)
 		{
-			Domain = domain;
+			Scope = scope;
 			_core = core;
 			Type = type;
 			Callback = callBack;
@@ -110,7 +110,7 @@ namespace BizHawk.Client.EmuHawk
 			ReadOnly = readOnly;
 		}
 
-		public string Domain { get; }
+		public string Scope { get; }
 		public Action Callback { get; }
 		public uint? Address { get; set; }
 		public uint? AddressMask { get; set; }
@@ -163,7 +163,7 @@ namespace BizHawk.Client.EmuHawk
 
 		private void AddCallback()
 		{
-			_core.MemoryCallbacks.Add(new MemoryCallback(Domain, Type, Name, Callback, Address, AddressMask));
+			_core.MemoryCallbacks.Add(new MemoryCallback(Scope, Type, Name, Callback, Address, AddressMask));
 		}
 
 		private void RemoveCallback()
diff --git a/BizHawk.Emulation.Common/Base Implementations/CallbackBasedTraceBuffer.cs b/BizHawk.Emulation.Common/Base Implementations/CallbackBasedTraceBuffer.cs
index 41270104ae..4a93abc213 100644
--- a/BizHawk.Emulation.Common/Base Implementations/CallbackBasedTraceBuffer.cs	
+++ b/BizHawk.Emulation.Common/Base Implementations/CallbackBasedTraceBuffer.cs	
@@ -95,7 +95,7 @@ namespace BizHawk.Emulation.Common
 
 			public uint? AddressMask => null;
 
-			public string Domain => ""; // This will be relevant if/when the trace logger can trace anything other than the system bus
+			public string Scope => ""; // This will be relevant if/when the trace logger can trace anything other than the system bus
 		}
 	}
 }
diff --git a/BizHawk.Emulation.Common/Base Implementations/MemoryCallbackSystem.cs b/BizHawk.Emulation.Common/Base Implementations/MemoryCallbackSystem.cs
index 3ec926a27a..dd5deb70f4 100644
--- a/BizHawk.Emulation.Common/Base Implementations/MemoryCallbackSystem.cs	
+++ b/BizHawk.Emulation.Common/Base Implementations/MemoryCallbackSystem.cs	
@@ -14,14 +14,14 @@ namespace BizHawk.Emulation.Common
 	/// <seealso cref="IMemoryCallbackSystem" />
 	public class MemoryCallbackSystem : IMemoryCallbackSystem
 	{
-		public MemoryCallbackSystem(string[] availableDomains)
+		public MemoryCallbackSystem(string[] availableScopes)
 		{
-			if (availableDomains == null)
+			if (availableScopes == null)
 			{
-				availableDomains = new[] { "System Bus" };
+				availableScopes = new[] { "System Bus" };
 			}
 
-			AvailableDomains = availableDomains;
+			AvailableScopes = availableScopes;
 			ExecuteCallbacksAvailable = true;
 
 			_reads.CollectionChanged += OnCollectionChanged;
@@ -41,13 +41,13 @@ namespace BizHawk.Emulation.Common
 
 		public bool ExecuteCallbacksAvailable { get; }
 
-		public string[] AvailableDomains { get; }
+		public string[] AvailableScopes { get; }
 
 		public void Add(IMemoryCallback callback)
 		{
-			if (!AvailableDomains.Contains(callback.Domain))
+			if (!AvailableScopes.Contains(callback.Scope))
 			{
-				throw new InvalidOperationException($"{callback.Domain} is not currently supported for callbacks");
+				throw new InvalidOperationException($"{callback.Scope} is not currently supported for callbacks");
 			}
 
 			switch (callback.Type)
@@ -74,38 +74,38 @@ namespace BizHawk.Emulation.Common
 			_empty = false;
 		}
 
-		private static void Call(ObservableCollection<IMemoryCallback> cbs, uint addr, string domain)
+		private static void Call(ObservableCollection<IMemoryCallback> cbs, uint addr, string scope)
 		{
 			for (int i = 0; i < cbs.Count; i++)
 			{
-				if (!cbs[i].Address.HasValue || (cbs[i].Domain == domain && cbs[i].Address == (addr & cbs[i].AddressMask)))
+				if (!cbs[i].Address.HasValue || (cbs[i].Scope == scope && cbs[i].Address == (addr & cbs[i].AddressMask)))
 				{
 					cbs[i].Callback();
 				}
 			}
 		}
 
-		public void CallReads(uint addr, string domain)
+		public void CallReads(uint addr, string scope)
 		{
 			if (_hasReads)
 			{
-				Call(_reads, addr, domain);
+				Call(_reads, addr, scope);
 			}
 		}
 
-		public void CallWrites(uint addr, string domain)
+		public void CallWrites(uint addr, string scope)
 		{
 			if (_hasWrites)
 			{
-				Call(_writes, addr, domain);
+				Call(_writes, addr, scope);
 			}
 		}
 
-		public void CallExecutes(uint addr, string domain)
+		public void CallExecutes(uint addr, string scope)
 		{
 			if (_hasExecutes)
 			{
-				Call(_execs, addr, domain);
+				Call(_execs, addr, scope);
 			}
 		}
 
@@ -286,7 +286,7 @@ namespace BizHawk.Emulation.Common
 
 	public class MemoryCallback : IMemoryCallback
 	{
-		public MemoryCallback(string domain, MemoryCallbackType type, string name, Action callback, uint? address, uint? mask)
+		public MemoryCallback(string scope, MemoryCallbackType type, string name, Action callback, uint? address, uint? mask)
 		{
 			if (type == MemoryCallbackType.Execute && !address.HasValue)
 			{
@@ -298,7 +298,7 @@ namespace BizHawk.Emulation.Common
 			Callback = callback;
 			Address = address;
 			AddressMask = mask ?? 0xFFFFFFFF;
-			Domain = domain;
+			Scope = scope;
 		}
 
 		public MemoryCallbackType Type { get; }
@@ -306,6 +306,6 @@ namespace BizHawk.Emulation.Common
 		public Action Callback { get; }
 		public uint? Address { get; }
 		public uint? AddressMask { get; }
-		public string Domain { get; }
+		public string Scope { get; }
 	}
 }
diff --git a/BizHawk.Emulation.Common/Interfaces/IMemoryCallbackSystem.cs b/BizHawk.Emulation.Common/Interfaces/IMemoryCallbackSystem.cs
index c196795e6e..7e130b1dae 100644
--- a/BizHawk.Emulation.Common/Interfaces/IMemoryCallbackSystem.cs
+++ b/BizHawk.Emulation.Common/Interfaces/IMemoryCallbackSystem.cs
@@ -42,23 +42,29 @@ namespace BizHawk.Emulation.Common
 		/// If no address is specified the callback will be hooked to all addresses
 		/// Note: an execute callback can not be added without an address, else an InvalidOperationException will occur
 		/// </summary>
-		/// <exception cref="InvalidCastException">Thrown when the <see cref="IMemoryCallback.Domain"/> property of the <see cref="IMemoryCallback"/> is not in the <see cref="AvailableDomains"/></exception>
+		/// <exception cref="InvalidCastException">Thrown when the <see cref="IMemoryCallback.Scope"/> property of the <see cref="IMemoryCallback"/> is not in the <see cref="AvailableScopes"/></exception>
 		void Add(IMemoryCallback callback);
 
 		/// <summary>
 		/// Executes all Read callbacks for the given address and domain
 		/// </summary>
-		void CallReads(uint addr, string domain);
+		/// <param name="addr">The address to check for callbacks</param>
+		/// <param name="scope">The scope that the address pertains to. Must be a value in <see cref="AvailableScopes"></param>
+		void CallReads(uint addr, string scope);
 
 		/// <summary>
 		/// Executes all Write callbacks for the given address and domain
 		/// </summary>
-		void CallWrites(uint addr, string domain);
+		/// <param name="addr">The address to check for callbacks</param>
+		/// <param name="scope">The scope that the address pertains to. Must be a value in <see cref="AvailableScopes"></param>
+		void CallWrites(uint addr, string scope);
 
 		/// <summary>
 		/// Executes all Execute callbacks for the given address and domain
 		/// </summary>
-		void CallExecutes(uint addr, string domain);
+		/// <param name="addr">The address to check for callbacks</param>
+		/// <param name="scope">The scope that the address pertains to. Must be a value in <see cref="AvailableScopes"></param>
+		void CallExecutes(uint addr, string scope);
 
 		/// <summary>
 		/// Removes the given callback from the list
@@ -76,10 +82,10 @@ namespace BizHawk.Emulation.Common
 		void Clear();
 
 		/// <summary>
-		/// A list of available memory domains that a the <see cref="IMemoryCallback.Domain"/> property of the <see cref="IMemoryCallback"/>  can have
+		/// A list of available "scopes" (memory domains, cpus, etc) that a the <see cref="IMemoryCallback.Scope"/> property of the <see cref="IMemoryCallback"/> can have
 		/// Passing a <see cref="IMemoryCallback"/> into the <see cref="Add(IMemoryCallback)"/> method that is not in this list will result in an <seealso cref="InvalidOperationException"/>
 		/// </summary>
-		string[] AvailableDomains { get; }
+		string[] AvailableScopes { get; }
 	}
 
 	/// <summary>
@@ -93,7 +99,7 @@ namespace BizHawk.Emulation.Common
 		Action Callback { get; }
 		uint? Address { get; }
 		uint? AddressMask { get; }
-		string Domain { get; }
+		string Scope { get; }
 	}
 
 	public enum MemoryCallbackType