J31, J.31 or J-31 may refer to :
== Vehicles == British Aerospace Jetstream J31, a British airliner Nissan Teana J31, a Japanese sedan , a Makar-class survey ship of the Indian Navy Shenyang J-31, a Chinese fighter jet LNER Class J31, a class of British steam locomotives
Discovered by embedding cosine similarity (sentence-transformers MiniLM, 384-dim).