noun Geology.
a long, narrow or oval, smoothly rounded hill of unstratified glacial drift.

1825–35; drum2 + -lin, variant of -ling1

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World English Dictionary
drumlin (ˈdrʌmlɪn)
a streamlined mound of glacial drift, rounded or elongated in the direction of the original flow of ice
[C19: from Irish Gaelic druim ridge + -lin-ling1]

Collins English Dictionary - Complete & Unabridged 10th Edition
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Word Origin & History

1833, dim. of drum (1725) "ridge or long, narrow hill," often separating two parallel valleys, from Gael. & Ir. druim "back, ridge."
Online Etymology Dictionary, © 2010 Douglas Harper
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American Heritage
Science Dictionary
drumlin   (drŭm'lĭn)  Pronunciation Key 

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An extended, oval hill or ridge of compacted sediment deposited and shaped by a glacier. Drumlins are typically about 30 m (98 ft) high and are longer than they are wide. They have one steep and one gentle slope along their longest axis, which is parallel to the direction of the glacier's movement. The steepest slope faces the direction from which the glacier originated, and the gentler slope faces the direction in which the glacier was advancing.
The American Heritage® Science Dictionary
Copyright © 2002. Published by Houghton Mifflin. All rights reserved.
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Encyclopedia Britannica


oval or elongated hill believed to have been formed by the streamlined movement of glacial ice sheets across rock debris, or till. The name is derived from the Gaelic word druim ("rounded hill," or "mound") and first appeared in 1833.

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Encyclopedia Britannica, 2008. Encyclopedia Britannica Online.
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Example sentences
The writer prefers to restrict the name drumlin to those drift hills which show clearly the molding effect of the advancing ice.
Soils in the drumlin are described as dense silty to gravelly loam.
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