or ogam writing or ogum writing
Alphabetic script used for writing the Irish and Pictish (see Pict s) languages on stone monuments, mostly 0441; AD 400600.
In its simplest form, it consists of four sets of strokes, or notches, each set containing five letters composed of from one to five strokes, thus creating 20 letters. A fifth set of five symbols, called forfeda ("extra letters"), was probably a later development. Most inscriptions are short and consist only of names. Of the more than 400 inscriptions known, about 330 are from Ireland.