Item waiter may use, one supplying milk and fish (3,4)
I believe the answer is:
tea tray
'item' is the definition.
The answer and definition can be both man-made objects as well as being singular nouns.
Maybe you can see a link between them that I don't see?
'waiter may use one supplying milk and fish' is the wordplay.
I cannot really understand how this works, but
'one' could be 'a' (a thing is one thing) and 'a' is found within the answer.
'fish' could be 'tetra' (tetra is a kind of fish) and 'tetra' is located in the leftover letters.
A single letter 'y' remains which might be clued in a way I don't see.
This explanation may well be incorrect...
Can you help me to learn more?
(Other definitions for tea tray that I've seen before include "Delivery method for China" , "Pot, cups carrier" , "food transport" , "Where service may be held" , "Domestic carrier" .)