thumb|right|The north gate of Cardiff Castle, following the old Roman fortifications and rebuilt along Roman lines.
thumb|right|The north gate of Cardiff Castle, following the old Roman fortifications and rebuilt along Roman lines.
Caer (; or '') is a placename element in Welsh meaning "stronghold", "fortress", or "citadel", roughly equivalent to an Old English suffix (-ceaster) now variously written as , , and .
Discovered by embedding cosine similarity (sentence-transformers MiniLM, 384-dim).