diff --git a/app.py b/app.py
index bad51c4..7d0d491 100644
--- a/app.py
+++ b/app.py
@@ -32,7 +32,6 @@ async def lifespan(app: FastAPI):
     except Exception:
         pass
     get_slant_index()
-    get_mosaic_indexes()
     yield
 
 
@@ -1094,79 +1093,6 @@ def _ranked(words, exclude: set[str], limit: int) -> list[dict]:
     return out
 
 
-_phones_index: dict[str, list[str]] | None = None
-_rime_index: dict[str, list[str]] | None = None
-
-
-SQUEEZABLE = {"AH", "IH", "EH", "UH", "ER"}  # vowels that reduce unstressed
-
-
-def _squeeze(phones: str) -> str:
-    return " ".join("x" if p in SQUEEZABLE else p for p in phones.split())
-
-
-def get_mosaic_indexes():
-    """full-phones -> words (exact and vowel-squeezed) and rime -> words,
-    normalized, built once."""
-    global _phones_index, _rime_index
-    if _phones_index is None:
-        pronouncing.init_cmu()
-        pidx: dict[str, list[str]] = defaultdict(list)
-        ridx: dict[str, list[str]] = defaultdict(list)
-        for w, phones in pronouncing.pronunciations:
-            if not w.isalpha() or zipf_frequency(w, "en") < 3.0:
-                continue
-            ph = _norm_r(phones)
-            bare = DIGITS.sub("", ph)
-            pidx[bare].append(w)
-            squeezed = _squeeze(bare)
-            if squeezed != bare:
-                pidx[squeezed].append(w)
-            ridx[DIGITS.sub("", pronouncing.rhyming_part(ph))].append(w)
-        _phones_index, _rime_index = pidx, ridx
-    return _phones_index, _rime_index
-
-
-def mosaics_for(w: str, limit: int) -> list[dict]:
-    """Two-word phrases that rhyme with w perfectly: split its rime at
-    every consonant boundary and search both halves (placement ->
-    race + meant)."""
-    phones = phones_for(w)
-    if not phones:
-        return []
-    # anchor at the FIRST vowel: tonight (AH N AY T) splits into a + night
-    pl = DIGITS.sub("", phones).split()
-    vi = next((i for i, p in enumerate(pl) if p in ARPA_VOWELS), None)
-    if vi is None:
-        return []
-    rime = pl[vi:]
-    pidx, ridx = get_mosaic_indexes()
-    pairs: dict[str, float] = {}
-    for i in range(1, len(rime)):
-        left, right = " ".join(rime[:i]), " ".join(rime[i:])
-        if not any(p in ARPA_VOWELS for p in rime[:i]):
-            continue
-        if not any(p in ARPA_VOWELS for p in rime[i:]):
-            continue
-        # exact tail match, plus squeezed: where the target carries a
-        # reducible vowel, the tail word's own vowel may squeeze to fit
-        # (placement -> place + meant, the EH collapsing to a schwa)
-        tails = {right: 2.0, _squeeze(right): 0.0}
-        for a in ridx.get(left, []):
-            for tail_key, bonus in tails.items():
-                for b in pidx.get(tail_key, []):
-                    if a == w or b == w:
-                        continue
-                    phrase = f"{a} {b}"
-                    score = (zipf_frequency(a, "en")
-                             + zipf_frequency(b, "en") + bonus
-                             - (1.5 if len(a) < 2 else 0))
-                    if score > pairs.get(phrase, 0):
-                        pairs[phrase] = score
-    ranked = sorted(pairs.items(), key=lambda kv: (-kv[1], kv[0]))
-    return [{"word": p, "syl": None} for p, _ in ranked[:limit]]
-
-
 @app.get("/api/word")
 def word_info(word: str):
     """Phonetic anatomy of a word: phones, syllables, stress, rime."""
@@ -1192,9 +1118,6 @@ def lookup(word: str, mode: str = "rhyme", limit: int = 60):
         sections = synonyms_for(w, limit)
         return {"word": w, "mode": mode, "known": bool(sections),
                 "sections": sections}
-    if mode == "mosaic":
-        words = mosaics_for(w, limit)
-        return {"word": w, "mode": mode, "known": bool(words), "words": words}
     phones = phones_for(w)
     if not phones:
         return {"word": w, "mode": mode, "known": False, "words": []}
diff --git a/static/index.html b/static/index.html
index 292ff45..970e1f0 100644
--- a/static/index.html
+++ b/static/index.html
@@ -298,7 +298,6 @@ Double-click any word to look it up on the right."></textarea>
       <div class="seg" id="modeSeg">
         <button class="active" data-mode="rhyme">Rhymes</button>
         <button data-mode="syn">Synonyms</button>
-        <button data-mode="mosaic" title="Two-word phrases that rhyme with it">Mosaics</button>
       </div>
       <div id="defBox"></div>
       <div id="lookupResults">
@@ -648,18 +647,18 @@ async function doLookup(){
   const word = document.getElementById('lookupInput').value.trim();
   if(!word) return;
   document.getElementById('tab-lookup').scrollTop = 0;
-  showDefinition(word);  // the definition always pins on top
+  // the card belongs to the word, not the submode: rebuild only when
+  // the word changes, and respect a dismissal until then
+  if(word.toLowerCase() !== defWord){
+    defWord = word.toLowerCase();
+    defDismissed = false;
+    showDefinition(word);
+  }
   resultsBox.innerHTML = '<p class="muted">Searching…</p>';
   try{
     const r = await fetch(`/api/lookup?word=${encodeURIComponent(word)}&mode=${mode}`);
     const data = await r.json();
-    if(mode === 'mosaic'){
-      if(!data.known){
-        resultsBox.innerHTML = `<p class="muted">No clean two-word split for “${esc(word)}” — mosaics need a sound the dictionary can rebuild from two words (try placement, creation, tonight).</p>`;
-        return;
-      }
-      renderMosaics(word, data.words);
-    }else if(mode === 'syn'){
+    if(mode === 'syn'){
       if(!data.known){
         resultsBox.innerHTML = `<p class="muted">No synonyms found for “${esc(word)}”.</p>`;
         return;
@@ -694,6 +693,7 @@ function wireChips(){
 
 /* ---------- definition card (free dictionary API) ---------- */
 const defBox = document.getElementById('defBox');
+let defWord = null, defDismissed = false;
 function defCard(word, inner){
   defBox.innerHTML = `
     <div class="defcard">
@@ -705,7 +705,7 @@ function defCard(word, inner){
       </div>
     </div>`;
   defBox.querySelector('#defInsert').addEventListener('click', ()=> insertAtCursor(word));
-  defBox.querySelector('.defx').addEventListener('click', ()=>{ defBox.innerHTML=''; });
+  defBox.querySelector('.defx').addEventListener('click', ()=>{ defBox.innerHTML=''; defDismissed = true; });
 }
 function draftMates(word){
   if(!analysis) return [];
@@ -759,15 +759,6 @@ function renderChips(label, words){
   resultsBox.innerHTML = `<div class="res-label">${label}</div>` + chipHtml(words.slice(0,50));
   wireChips();
 }
-function renderMosaics(word, items){
-  let h = `<div class="res-label">two-word rhymes for “${esc(word)}” — click to insert</div>`;
-  h += chipHtml(items.map(d=>d.word));
-  resultsBox.innerHTML = h;
-  resultsBox.querySelectorAll('.chip').forEach(c=>{
-    c.addEventListener('click', ()=> insertAtCursor(c.dataset.w));
-  });
-}
-
 function renderSections(word, sections){
   if(!sections.length){ resultsBox.innerHTML = `<p class="muted">No synonyms for “${esc(word)}”.</p>`; return; }
   let h = '';
diff --git a/tests/test_rhymes.py b/tests/test_rhymes.py
index f0ea0c5..18d5db1 100644
--- a/tests/test_rhymes.py
+++ b/tests/test_rhymes.py
@@ -519,16 +519,6 @@ def test_secondary_pronunciation_stays_local():
 
 # -------------------------------------------------------------- new tools
 
-def test_mosaic_generator():
-    from app import mosaics_for
-    words = {m["word"] for m in mosaics_for("placement", 20)}
-    assert "place meant" in words
-    creation = {m["word"] for m in mosaics_for("creation", 20)}
-    assert "way shun" in creation
-    tonight = {m["word"] for m in mosaics_for("tonight", 20)}
-    assert "a night" in tonight
-
-
 def test_word_info():
     from app import word_info
     info = word_info(word="tonight")