Right, what you've described are the common dictionary definitions. Those are the definitions a misbehaving juror might find, that would probably cause them to incorrectly answer a question such as the following in some circumstances:
"Did the defendant possess a copy of any work for which they were not the author?"
Because potential offenses (such as "possessing a ____ copy") are based on the same definitions as the rest of the statute, it is the job of the lawyers and judge to make sure that the jurors know, in attempting to answer that question, that according to US copyright law...
“Copies” are material objects, other than phonorecords, in which a work is fixed by any method now known or later developed, and from which the work can be perceived, reproduced, or otherwise communicated, either directly or with the aid of a machine or device. The term “copies” includes the material object, other than a phonorecord, in which the work is first fixed.
which means that the original and any duplicates are all "copies", and laws [in this section] that refer or apply to a "copy" apply to the original as well.
and
In the case of a work made for hire, the employer or other person for whom the work was prepared is considered the author for purposes of this title
which means that laws [in this section] that refer or apply to the "author" of a work apply to the employer, not the employee.