Definitions of preliminary design on the Web:

* Preliminary Design is the first phase of the design process...
http://info.med.yale.edu/fdo/pmc/process/pd.html

* The engineering and environmental studies associated with the development and comparison of alternate locations, alternate alignments, detailed analysis, ongoing public and agency interaction project review and final selection of a project alternative.
www.eastbradybridge.com/about/glossary.asp

* A construction project's configuration drawings and methods specifications up to approximately the 30 percent level of completedness, or at a (similar) level which allows for final design and construction bidding to proceed.
www.fta.dot.gov/library/planning/prob/glossary.html

* The step of the engineering design method where some of the more promising ideas are explored in more detail.
highered.mcgraw-hill.com/sites/0072480823/student_view0/glossary.html

* The design phase between schematics and construction documents. Also known as the "design development" phase in the architectural and engineering industry.
www.usg.edu/ref/capital/bppmanual/defs.phtml