From PIE *kel- (to rise) — the same root that through Latin gives 'column,' 'culminate,' and 'excel.'
A naturally raised area of land, smaller and lower than a mountain, with a rounded or gently sloping summit.
From Old English 'hyll,' from Proto-Germanic *hulliz or *hulnijaz, from PIE *kel- ('to rise, to be prominent, to project'). This ancient root is one of the most productive in Indo-European for landscape terms, also giving Latin 'collis' ('hill'), 'columna' ('column'), 'culmen' ('summit'), and 'excellere' ('to rise above, to excel'). The English word has remained remarkably stable in both form and meaning