The distance setting (of a lens) that gives the greatest possible range of distances at which objects appear to be in focus.
Good lenses have means of indicating the depth of field for a given aperture setting. The hyperfocal setting for a given aperture is obtained by placing the most distant limit of the depth of field range on ¥.
The corresponding 'hyperfocal distance' is the actual distance setting when the hyperfocal criterion has been met.
Note that wide-angle lenses have an extremely large depth of field, and therefore, unless being used for extreme close-up work, are best set to the hyperfocal distance and left alone (refocusing is only necessary if the aperture is changed).