hummock[
'hʌmәk]
n. 圆丘,

丘, 山岗
hummock[ noun ]a small natural hill<noun.object> 
Hummock \Hum"mock\, n. [Prob. a dim. of hump. See {Hump}.]
1. A rounded knoll or hillock; a rise of ground of no great
extent, above a level surface.
2. A ridge or pile of ice on an ice field.
3. Timbered land. See {Hammock}. [Southern U.S.]