What is a collective noun of chairs?

There isn't a commonly used, single, collective noun specifically for chairs.

However, here are some options you can use depending on the context:

General:

* Set of chairs

* Group of chairs

* Collection of chairs

* Arrangement of chairs

More specific:

* Suite of chairs (for a matching set)

* Row of chairs

* Circle of chairs

* Stack of chairs (if they're stacked)

You can also use more descriptive phrases to convey the specific type of collection, like "a gathering of antique chairs" or "a display of velvet chairs."