This is an irregular feature - both in frequency and oddness - dedicated to a word I came across that I have never previously used.
ogham (OH-ehm) n. (alternate spelling: ogam) An ancient alphabet of the Celtic people, consisting of a group of parallel lines that meet or cross a base-line.
Rhyming with "poem" and using a twenty-character alphabet, Ogham letters were represented by varying strokes and notches, and the text is read beginning from the bottom left-hand side of a stone, continuing upward, across the top and down the right-hand side in the case of longer inscriptions. Five additional letters serve to convey diphthongs.
Ogham inscriptions are found in Wales, Ireland, Scotland, England, Shetland, and on the Isle of Man, typically used as territorial markers and memorials.
Eighth-century stone etched with Ogham characters. The inscription reads 'Benddact anim L.', or "a blessing on the soul of L.
The heyday of Ogham appears to have been between the fifth and seventh centuries CE (common era). The names of the twenty primary letters correspond to the names of trees sacred to the Druids.
The Ogham alphabet is believed to have been named after the Irish god Ogma, and a plausible theory of the origins of Ogham is that the script evolved out of a system of tallies used for accounting purposes.