diff --git a/rslib/backend.proto b/rslib/backend.proto
index 056536afc..2cfcd1dd7 100644
--- a/rslib/backend.proto
+++ b/rslib/backend.proto
@@ -89,6 +89,7 @@ service BackendService {
     rpc SearchNotes (SearchNotesIn) returns (SearchNotesOut);
     rpc NegateSearch (String) returns (String);
     rpc ConcatenateSearches (ConcatenateSearchesIn) returns (String);
+    rpc ReplaceSearchTerm (ReplaceSearchTermIn) returns (String);
     rpc FindAndReplace (FindAndReplaceIn) returns (UInt32);
 
     // scheduling
@@ -755,6 +756,20 @@ message BuiltinSearchOrder {
     bool reverse = 2;
 }
 
+message ConcatenateSearchesIn {
+    enum Separator {
+        AND = 0;
+        OR = 1;
+    }
+    Separator sep = 1;
+    repeated string searches = 2;
+}
+
+message ReplaceSearchTermIn {
+    string search = 1;
+    string replacement = 2;
+}
+
 message CloseCollectionIn {
     bool downgrade_to_schema11 = 1;
 }
diff --git a/rslib/src/backend/mod.rs b/rslib/src/backend/mod.rs
index b76df4359..485666f88 100644
--- a/rslib/src/backend/mod.rs
+++ b/rslib/src/backend/mod.rs
@@ -435,10 +435,15 @@ impl BackendService for Backend {
     fn negate_search(&self, input: pb::String) -> Result<pb::String> {
         Ok(negate_search(&input.val)?.into())
     }
+    
     fn concatenate_searches(&self, input: pb::ConcatenateSearchesIn) -> Result<pb::String> {
         Ok(concatenate_searches(input.sep, &input.searches)?.into())
     }
 
+    fn replace_search_term(&self, input: pb::ReplaceSearchTermIn) -> Result<pb::String> {
+        Ok(replace_search_term(&input.search, &input.replacement)?.into())
+    }
+
     fn find_and_replace(&self, input: pb::FindAndReplaceIn) -> BackendResult<pb::UInt32> {
         let mut search = if input.regex {
             input.search
diff --git a/rslib/src/search/parser.rs b/rslib/src/search/parser.rs
index 2be9a3d3b..b82f28237 100644
--- a/rslib/src/search/parser.rs
+++ b/rslib/src/search/parser.rs
@@ -50,7 +50,7 @@ pub(super) enum Node<'a> {
     Search(SearchNode<'a>),
 }
 
-#[derive(Debug, PartialEq)]
+#[derive(Debug, PartialEq, Clone)]
 pub(super) enum SearchNode<'a> {
     // text without a colon
     UnqualifiedText(Cow<'a, str>),
@@ -90,7 +90,7 @@ pub(super) enum SearchNode<'a> {
     WordBoundary(Cow<'a, str>),
 }
 
-#[derive(Debug, PartialEq)]
+#[derive(Debug, PartialEq, Clone)]
 pub(super) enum PropertyKind {
     Due(i32),
     Interval(u32),
@@ -99,7 +99,7 @@ pub(super) enum PropertyKind {
     Ease(f32),
 }
 
-#[derive(Debug, PartialEq)]
+#[derive(Debug, PartialEq, Clone)]
 pub(super) enum StateKind {
     New,
     Review,
@@ -111,7 +111,7 @@ pub(super) enum StateKind {
     Suspended,
 }
 
-#[derive(Debug, PartialEq)]
+#[derive(Debug, PartialEq, Clone)]
 pub(super) enum TemplateKind<'a> {
     Ordinal(u16),
     Name(Cow<'a, str>),
diff --git a/rslib/src/search/writer.rs b/rslib/src/search/writer.rs
index 1a866b9cf..773270e2a 100644
--- a/rslib/src/search/writer.rs
+++ b/rslib/src/search/writer.rs
@@ -9,6 +9,7 @@ use crate::{
     search::parser::{parse, Node, PropertyKind, SearchNode, StateKind, TemplateKind},
 };
 use itertools::Itertools;
+use std::mem;
 
 /// Take an Anki-style search string and convert it into an equivalent
 /// search string with normalized syntax.
@@ -55,6 +56,31 @@ pub fn concatenate_searches(sep: i32, searches: &[String]) -> Result<String> {
     ))
 }
 
+/// Take two Anki-style search strings. If the second one evaluates to a single search
+/// node, replace with it all search terms of the same kind in the first search.
+/// Then return the possibly modified first search.
+pub fn replace_search_term(search: &str, replacement: &str) -> Result<String> {
+    let mut nodes = parse(search)?;
+    let new = parse(replacement)?;
+    if let [Node::Search(search_node)] = &new[..] {
+        fn update_node_vec<'a>(old_nodes: &mut [Node<'a>], new_node: &SearchNode<'a>) {
+            fn update_node<'a>(old_node: &mut Node<'a>, new_node: &SearchNode<'a>) {
+                match old_node {
+                    Node::Not(n) => update_node(n, new_node),
+                    Node::Group(ns) => update_node_vec(ns, new_node),
+                    Node::Search(n) => {
+                        if mem::discriminant(n) == mem::discriminant(new_node) {
+                            *n = new_node.clone();
+                        }
+                    }
+                    _ => (),
+                }
+            }
+            old_nodes.iter_mut().for_each(|n| update_node(n, new_node));
+        }
+        update_node_vec(&mut nodes, search_node);
+    }
+    Ok(write_nodes(&nodes))
 }
 
 fn write_nodes<'a, I>(nodes: I) -> String