Ogma, modern spelling Oghma, is a member of the Tuatha De Danaan and may possibly be related to the Gaelic god, Ogmios.
He often appears as a triad with Lugh and the Dagda (The Dagda is his brother and Lugh is his half-brother), who are sometimes collectively known as the trí dée dána or three gods of skill. His father is Elatha and his mother is usually given as Ethliu, also known as Étaín.
He is portrayed as a swarthy man whose battle ardor was so great that he had to be chained and held back by other warriors until the right moment for military action occurred. He fights in the first battle of Mag Tuired, when the Tuatha Dé take Ireland from the Fir Bolg.. Under the reign of Bres, when the Tuatha Dé are reduced to servitude, Ogma is forced to carry firewood, but nonetheless is the only one of the Tuatha Dé who proves his athletic and martial prowess in contests before the king. When Bres is overthrown and Nuadu restored, Ogma is his champion. His position is threatened by the arrival of Lugh at the court, so Ogma challenges him by lifting and hurling a great flagstone, which normally required eighty oxen to move it, out of Tara, but Lugh answers the challenge by hurling it back. When Nuadu hands command of the Battle of Mag Tuired to Lugh, Ogma becomes Lugh's champion, and promises to repel the Fomorian king, Indech, and his bodyguard, and to defeat a third of the enemy.
He is said to have invented the Ogham alphabet, which is named after him. It is considered the first written language of Ireland, one which uses very basic designs to convey meaning. Ogham sticks were made out of various kinds of tree branches and then, according to many stories from Ireland, cast to divine news about what would be going on in the world.
One way to honor him today is through the offer of a poem or song, since he is considered the "Father of language".