Grammar check

[sam239]

In the sentence, "I don't know where he is at," what is the unnecessary "at" called? I thought it was a dangling participle, but it turns out that is something totally different.

[jjimm]

How about "(trailing) redundant preposition"?

[RealityChuck]

There are different terms, depending on how you choose to intepret the sentence.

Quirk and Greenbaum would probably call it a "postposed preposition."

It could also be termed the particle of a verb (i.e., the verb "to be at," which is different from the verb "to be").

It is certainly a nonstandard usage, which make nomenclature that much more difficult.