"conceptual plans"

[Arnold M. Zwicky]

I came across this puzzling expression in the Palo Alto Daily News of
6/16/05, in "High school plans unveiled" by Luke Stangel, which begins:

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Conceptual plans for a new $17 million performing arts center at
Menlo-Atherton High School were unveiled to the public last night at
a meeting planned for gathering feedback.
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The "concept" in "conceptual plans becomes clearer in a later paragraph:

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Hodgetts + Fung have designed several high-profile public buildings,
such as the Minneapolis Orchestra Amphitheater.  Their design--which
Craig Hodgetts admitted was still a "very loose concept"--faces
Middlefield Road and has room for a 500-seat theater and 100-seat
orchestra.
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Later it becomes clear that the conceptual plans are not mere rough
sketches, since numerous specific details are mentioned in the story.

Google gives ca. 31,700 webhits for "conceptual plans", including the
following definition in the home design context:

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Conceptual plans are home designs that have not yet been
finalized. ... Each of
the conceptual plans includes a "copyright release" that gives you
and your ...
www.conceptualhouseplans.com/faqs.shtml
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I would have used "preliminary plans" here, but I suppose that
architects and designers prefer to present themselves as dealing in
*concepts*.

I also noted the metonymy that has the *design* facing Middlefield Road.

arnold (zwicky at csli.stanford.edu)