Nomenclature (terms) explained:

Dr. Christine M. Rodrigue, from Department of Geography
California State University, Long Beach, CA, has a nice illustrated ppt of these terms on  A whole new vocabulary (2.3 meg download)

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The Mars Student Imaging Project,MSIP, has a clear basic illustration of features on pg 10-18  on: 

http://marsed.mars.asu.edu/sites/default/files/stem_resources/SM_MARS_IMAGE_ANALYSIS_2_16.pdf