What is a quaich? There is reference to a Quaich bar at a venue in Scotland, and also a Quaich trophy for one of the dog show classes. Can't find it in the dictionary though.
From the Gaelic 'cuach' meaning a dish, cup, or bowl. The word applied to anything of that shape including hollowed-out stones commonly used for grinding corn, and still to be found all over Scotland.
These days the word is mostly used in reference to a shallow drinking-bowl, as Allen says, though they generally do have handles.
Plenty of examples online, including here
It's a shallow drinking bowl from the Gaelic "Cuach". It usually has two handles on opposite sides so it can be passed round a group for a sip of whatever is in it - usually whisky! Modern ones are usually silver