Distance units are the units used by ArcView to display or indicate:
These measurements and dimensions are displayed on ArcView's status bar. Each
view has its own distance units setting, so you can choose the most appropriate
units for the particular view you are working with. The default is unknown.
2. From the Distance Units list, choose the units you wish to use.
3. Press OK.
A view's distance units setting is independent of its map units setting.
Setting distance units
The results of measurements you make on a view with the 'Measure tool'.
The dimensions of shapes you draw on a view with the 'Draw tool'.
The dimensions of the selection box you define when selecting features in a
particular area on a view with the 'Select Feature tool'.
The distance tolerance one set of features are from another set in "Select By
Theme" dialog box.