Deiseal

From Irish deiseal, from Old Irish dessel, from Old Irish dess ("right, south") + sel ("turn").

In the eyes of our early forefathers the daily course of the Sun, bringing about the alternation of light and darkness and the regular succession of the seasons, was the most striking example that man had of that divine order of the universe which served as a model for order and justice in terrestrial affairs. Hence to go dessel or righthandwise, thus imitiating the course of the sun, was not only the right way to make a journey, but was likewise beneficial in other affairs of life, and was likely to lead to a prosperous result; whereas to go in the contrary direction (tuaithbel) would be a violation of the established order and would lead to harm. â€” T. F. O'Rahilly, Early Irish History and Mythology, Dublin (1946), pp. 296-297.

Full definition of deiseal

(plural deiseals)

Motion towards the right, in the direction of the hands of a clock or of the apparent motion of the sun; a turning in this direction.

deiseal

1922 James Joyce, Ulysses 366:Deshil Holles Eamus.
1814 Walter Scott, Waverley 24:The surgeon ... perambulated his couch three times, moving from east to west, according to the course of the sun ... which was called making the deasil.

A deprecation meaning May it go right, said to someone who sneezes or swallows something awry.

1794 ''Statistical Account of Scotland: Perthshire 11.521:If a person's meat or drink were to ... come against his breath, they instantly cry out, Deisheal! which is an ejaculation praying that it may go the right way.