http://en.wiktionary.org/wiki/%E6%9E%9C%E7%89%A9
I think the idea of it coming from 木だ物, with 木 being read using the older "こ" onyomi, but then later sound shift caused it to be pronounced "く" in this particular word.
I like the fact it now uses the 果 kanji, which contains 木 + 田...
木 = こ → sound shift to く when used in 木だ物
田 = た → rendaku to だ (like in names such as 山田【やまだ】)
木 + 田 = 果【く + た = くだ】
Although I don't think the fact 果 is made up of those two kanji actually has anything to do with why 果 is used to write that word. Probably just me being too imaginative. ^^
July 18, 2015 at 9:12am