What exactly does "predefined" mean?

[Leonard_Berkowitz@harvardpilgrim.org]

The PDL manual, s. v. USAGE, states, 'The usage must have been defined
previously. It can be one of the predefined usages that are supplied with
the PowerHouse dictionary, or it can be a usage that has previously been
defined by the USAGE statement. For informattion about the predefined
usages that are available, see Chapter 5, "Standard Elements and Usages".'

In Chapter 5 there is a column called FILLER. Is that not a predefined
usage?

The following code caused a PDL error:

Element FILLER01 &
  Usage FILLER

because it was explicitly looking for

Usage FILLER &
  Character Size 001

So what exactly does "predefined" mean? And of what use are "predefined
usages?"
===================
Leonard S. Berkowitz
Perot Health Care Systems
(Harvard Pilgrim Health Care account)
voice: 617-509-1212
fax:   617-509-3737
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