Haiku were originally short poems written in Japanese.
It's often said that they have five syllables in the first line, seven in the next, and five in the last.
This isn't usually true.
No, in fact Japanese haiku have five moras in the first line, seven in the next, and five in the last.
So what's a mora?
Well, it depends on which language you're talking about, and even then it's not easy to be exactly sure, but a short vowel is generally one mora, and a long one is two.
No, no, that isn't all there is to it. The English word rot is a two mora word because the end consonant of a stressed syllable counts as a mora. But then the last consonant of carrot isn't a mora, because it's not at the end of a stressed syllable. That's what people say.
On the other hand other people say something entirely different...
Anyway. In Japanese, a long vowel counts as two mora, and an n at the end of a syllable counts as one mora.
Take the word syasin, which means photograph:
Its syllables are two: sya and sin.
Its moras, though, are three: sya si and n.
There we are. A feast for bigheads and nit-pickers everywhere - and a reason why writing haiku is even harder than we thought.
Word To Use Today: haiku. Haiku are short, and pleasingly the word haiku itself is shorter than it was originally. To start with it was haikai no ku, which means light verse.