In all my time as a Perl dev (since 1996) I don't think I've ever heard the term "associative array" except at the start of `perldoc perldata` - which says they're known as hashes and then never uses the term again.

    DESCRIPTION
      Variable names
        Perl has three built-in data types: scalars, arrays of scalars, and
        associative arrays of scalars, known as "hashes". A scalar is a single
        string (of any size, limited only by the available memory), number, or a
        reference to something (which will be discussed in perlref). Normal
        arrays are ordered lists of scalars indexed by number, starting with 0.
        Hashes are unordered collections of scalar values indexed by their
        associated string key.

Hash is ubiquitous.

Yes they used to be called Associative Arrays. I think the change occurred between Perl4 & Perl5.

In Programming Perl it says "Associative Arrays" in 1st edition and "Hashes (Associative Arrays)" in 2nd edition.

NB. 2nd edition was the first to cover Perl5