Ogham (also ogam and ogom, /ˈɒɡəm/ OG-əm, Modern Irish: [ˈoː(ə)mˠ]; Middle Irish: ogum, ogom, later ogam [ˈɔɣəmˠ]) is an Early Medieval alphabet used primarily to write the early Irish language (in the "orthodox" inscriptions, 4th to 6th centuries AD), and later the Old Irish language (scholastic ogham, 6th to 9th centuries). There are roughly 400 surviving orthodox inscriptions on stone monuments throughout Ireland and western Britain, the bulk of which are in southern areas of the Irish province of Munster. The Munster counties of Cork and Kerry contain 60% of all Irish ogham stones. The largest number outside Ireland are in Pembrokeshire, Wales.
The inscriptions usually consist of personal names written in a set formula.