cutting word; kireji
A technical term in haiku and renga for a word that provides a pause or exclamation, such as や, かな, or けり. Used to create rhythm and emotional emphasis.
In haiku, the 'cutting word' plays an important role.
「古池や蛙飛びこむ水の音」の「や」は切れ字の一つだ。
The 'ya' in 'The old pond — a frog jumps in, the sound of water' is one of the cutting words.
Standard spelling for this literary term.
Abbreviated spelling; also common.
From 切れ (kire, 'cutting') + 字 (ji, 'character'). The term refers to words that 'cut' the flow of a poem.