What is "auctorum"

Auctorum (abbreviated auct. or auctt.), in botany and zoology is a term used to indicate that a name is used in the sense of a number of subsequent authors and not in its (different) sense as established by the original author. Auctorum is Latin and means of authors.

It is often used in conjunction with nec or non to indicate a misapplied name.

It may be qualified to indicate the number of authors, e.g. auctorum multorum (abbreviated auct. mult.), Latin for of many authors, indicates that many subsequent authors used a name in a different sense to the original author.