What is "great grey owl"

n. ''Strix nebulosa'', a very large owl.

The great grey owl or great gray owl (Strix nebulosa) is a very large owl, documented as the world's largest species of owl by length. It is distributed across the Northern Hemisphere, and it is the only species in the Strix (genus) found in both Eastern and Western Hemispheres. In some areas it is also called Phantom of the North, cinereous owl, spectral owl, Lapland owl, spruce owl, bearded owl, and sooty owl.