A peak's line parent is the closest higher peak on the highest ridge leading away from the peak's "key col". A col is the lowest point on the ridge between two summits and is roughly synonymous with pass, gap, saddle and notch. The highest col of a peak is its key col. If there is more than one ridge which can be followed to a higher peak then the line parent is the peak closest to the key col. Usually, a line parent must meet some prominence criteria, which might vary depending on the author and the location of the peak. [1] [2] [3]
There are at least two other kinds of peak parentage. Island parentage, which is also referred to as encirclement or topographic parentage; and source parentage. [1]
In topography, prominence measures the height of a mountain or hill's summit relative to the lowest contour line encircling it but containing no higher summit within it. It is a measure of the independence of a summit. A peak's key col is a unique point on this contour line and the parent peak is some higher mountain, selected according to various criteria.