core + attic (Attic Area): these terms have been either deprecated from the core or extentions, or removed from pending as not accepted into the full vocabulary.

commentCount

Canonical URL: http://schema.org/commentCount

Thing > Property > commentCount

The number of comments this CreativeWork (e.g. Article, Question or Answer) has received. This is most applicable to works published in Web sites with commenting system; additional comments may exist elsewhere.

Usage: Between 1000 and 10,000 domains
Values expected to be one of these types
Integer
Used on these types
CreativeWork

Schema Version 3.4