An abecedarius is a poem where the lines start with every letter of an alphabet, in order.
Abecedarii are very old, and no one knows how they started. They may have begun as a way of invoking the intrinsic magic of letters, but nowadays they tend to crop up more as a way of teaching children their alphabets.
Dr Seuss's ABC is a famous example, but it has been pointed out to nearly every child by one means or another that A is for Apple and that B is for Ball.
And that X causes all sorts of problems.
What's the point of knowing any of this stuff? Well, for me, knowing about abecedarii has soothed away one very longstanding irritation.
Psalm 119 is too long - it has 176 verses - which is ridiculous. Who's going to want to sing, or listen to, a song with 176 verses?
Now, it turns out that in the original Hebrew each eight verse section has all its lines starting with the same Hebrew letter. The initial letters of the first section start with the first letter of the Hebrew alphabet, the next section has lines starting with the second letter of the Hebrew alphabet, and the psalm goes on in this way, section by section, through the whole alphabet from beginning to end. (The mathematicians among you will already have deduced that the Hebrew alphabet has twenty two letters.)
So Psalm 119 is still ridiculous, but at least there's a reason for its being ridiculous. And now I find that in my late mother-in-law Doris's copy of the Bible, given to her as a Christmas present when she was aged eleven by someone who inscribes herself Auntie Dick, the sections of Psalm 119 do indeed have titles beginning with ALEPH and ending with TAU.
I hope someone explained this to poor little Doris.
But somehow I doubt it.
Word To Use Today: abecedarius. This is Mediaeval Latin for ABC Primer. In the form abecedary, the idea goes back to the 1400s.