Help identifying type of clause and its function

Hello, Bradaun, and welcome to the Grammar Exchange.

@Bradaun posted:

The commissioner, Mr. Bloggs, attended the meeting.

The subject is "The commissioner, Mr. Bloggs." Within the subject, "commissioner" is the head and "Mr. Bloggs" is an apposition. Notice that head and apposition can be swapped:

- Mr. Bloggs, the commissioner, attended the meeting. (In this case, "the commissioner" is the apposition.)

Thank you so much, Gustavo.  Very helpful.

@Bradaun posted:

(1) What is the name of the clause [i.e. "Mr. Bloggs"] used in this sentence, if it is a clause?

Hello, Bradaun, and welcome to the Grammar Exchange.

Gustavo has nicely explained the construction already. I'd just like to add that what you thought was a clause ("Mr. Bloggs") isn't a clause. It's a noun phrase.

Clauses have subjects and predicates. Thus, except in the case of imperatives (e.g. "Stop"), which have understood subjects, a clause is never just one word.