How to call this reducing bushing?

ccpyue

In my area, the incoming water pipe for sink faucet accepts 3/8" Female connector.

Now I've a faucet pipe on hand. I measures its compression female connector's inner diameter which is 19mm (too big for my incoming water pipe).

If I want to reduce it down to 3/8" so it can connect to the incoming pipe, how do we call this Reducing Bushing when shopping for it?

Thank you.