Definition of "deasil"

It consists, as is well known, in the person who makes the deasil walking three times round the person who is the object of the ceremony, taking care to move according to the course of the sun.

1827, Walter Scott, “The Two Drovers”, in Chronicles of the Canongate, volume 1, Edinburgh: Cadell and Co.

In Strathfillan, Perthshire, people are cured of insanity by being made to go three times deasil round a certain pool and then being plunged headlong into it.

1939, Wilson Dallam Wallis, Religion in Primitive Society‎, New York: F. S. Crofts & Co., page 160

Our clocks and watches turn deasil, and it would seem odd, almost contrary to nature, to have them turn widdershins. We read deasil, and Macaulay's widdershins writing ‘traced from the right on pages white’ was a conscious oddity of priests. Port was circulated deasil; to send it round widdershins was extremely unlucky. Playing cards are dealt deasil; we turn screws deasil. It is possible to trace our right-handedness to the perception of deasil as the normal direction, and widdershins as abnormal, topsy-turvy, unlucky.

1946, Herbert McKay, The World of Numbers, Cambridge University Press, page 42