Is set a concrete noun

Answer 1

It can be, but not always.

A set can be a concrete noun, referring to a set of tools, a set of drums, or a Chess set.

There are also abstract uses: a set of rules, or a set of values, would not be tangible, physical items.

Answer 2

The noun 'setting', a word for a place or type of surroundings where something is positioned, can be a concrete or an abstract noun, depending on use.

The noun setting is a concrete noun when used for the setting of a gemstone; or the setting for the controls of something; the surroundings where someone or something is; a word for a physical place or thing.

The noun setting is an abstract noun when used for the setting of a story, play, movie, etc.; the arrangement of dishes on a table (the dishes are concrete, the arrangement is a concept).