What Is This ? Coin?

It's hard to tell from the picture, but my guess would be that it's an imitation Ottoman coin.
This thread:
https://goccf.com/t/71951
and many others can be found if you use the "Search Coin Community" function at the top left of this page. Just enter "Imitation Ottoman"

Nope, it's imitation Ottoman Empire, all right. The "regnal year" visible in the bottom pic at about 8 o'clock reads "78". No Ottoman sultan ruled for that long; the sultan who acceded the throne in AH 1223 certainly didn't.

This piece is basically identical to the one in GO's old thread, linked by alganbagerap above. It's made of brass, and would originally have shined almost gold-like. Poor folks who couldn't afford real gold coins to dress themselves up nicely used these jewellery imitations instead.