ogham

Celtic script used in inscriptions in the Irish and Pictish languages, dating from the fourth century and found in Britain and Ireland. Its alphabet consists of 20 characters represented by notches or straight or diagonal strokes, varying in number from one to five and drawn or cut to the left, right, or directly through vertical lines or the edges of the vertical stone monuments on which they were carved. Besides stone monuments, they are traditionally said to have been used on shields and wooden staves, and occur in at least one 14th-century manuscript.