Garnedd Ugain, sometimes incorrectly referred to as "Crib y Ddysgl", is a mountain in Wales that forms part of the Snowdon Horseshoe. It is the second highest peak in Wales, and lies just under one kilometre north of Snowdon itself.
Both Garnedd Ugain and Crib y Ddysgl appear on the Ordnance Survey's maps of the area. The name Crib Y Ddysgl refers to the east ridge whilst the summit is Garnedd or Carnedd Ugain.
Crib y Ddysgl (meaning "ridge of the dish" in Welsh) is the name used by Alan Dawson for the peak's listing as a Hewitt.
Carnedd Ugain in Welsh means "Cairn of the Twenty" (the form Garnedd is the result of soft mutation). This was named after the Roman legion based in Caernarfon.
The web pages of the Welsh Mountaineering Club suggest that the name could also be a corruption of "Carnedd Wgon", and so named after the prince Wgon sung of by Dafydd ap Gwilym or possibly after the 13th century poet Gwgon Brydydd.