Ghyll or Gill is used for a stream or narrow valley in the North of England and other parts of the United Kingdom. The word originates from the Old Norse Gil. Examples include:
Where the word Ghyll refers to a valley, the stream flowing through it is often referred to as a Beck: for example in Swaledale, Gunnerside Beck flows through Gunnerside Ghyll. Beck is also used as a more general term for streams in the north of England. In the North Pennines, the word Sike is found in similar circumstances. This is particularly common in the Appleby Fells area where it significantly outnumbers the becks and gills; it can also be seen in the name of Eden Sike Cave in Mallerstang.