|French language term for the also used (correct English language term kp)|
|Used on these elements|
|Tools for this tag|
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Similar pages for structural reference: Key:religion, Key:waterway.
PK comes from the French term Point kilométrique which in English is probably known as milepost, kilometre post or motorway locator sign. It indicates the distance in kilometres from a defined point of reference (other units can be used by adding them as for other similar keys).
kp=* is also mentioned on this page as the correct English language term (short for kilometre post), but a discussion on the tagging list in May 2013 suggests distance=* is a better choice than either pk=* or kp=*.