What does 14 kt PS mean on jewelry?

Do you mean Plate? or "Plat"

If the ring is marked 14k plate, it's plated.

If the ring is marked 14k plat- it's likely that the ring is bi-metal mixed with gold and platinum, commonly it will have white metal around any stones.. If there are no stones possibly a white accent on certain parts of the ring.

Now, if the ring really says "Plai" - It could be the makers name, not sure!