Parents refers to a larger category under which an object falls. For example, theAconcagua mountain page has the 'Aconcagua Group' and the 'Seven Summits' asparents and is a parent itself to many routes, photos, and Trip Reports.
Related objects are relevant to each other in some way, but they don't form a parent/child relationship. Also, they don't necessarily share the same parent.
Page Type:
