The Cornish surname Carlyon, like all Cornish surnames is of locative origin, referring to the place where the initial bearer lived or held land, thus affording him a suitable means of identity within the local community.

In this instance, the name derives from the county of Cornwall, called Carlyon Bay, a coastal area located some 2 miles to the east of St Austell. The place name itself originated from France, from a place there called Carlehon, in Britanny, and was undoubtedly introduced into Britain with the Norman Conquest of 1066.