I didn't realise "bokeh" was a Japanese word. That's really cool. Seems like it uses this kanji 暈 [1] meaning "corona" or "halo" (in turn made up of the "sun" kanji, "car" kanji and "crown" radical–I'm not sure if there's a historical reason for this but it makes it easy to remember at least).
Boke (meaning blur) is from a combination of kanji 暈 (bo) and hiragana け (ke). You'll notice that "bokeh" doesn't look like usual romaji (Japanese romanization) spelling, since it would normally be transliterated as boke. It was spelled bokeh with the extra 'h' to avoid accidental pronunciation like poke.
Thanks for the info. I just realised too (thanks to a friend) that the kanji might originate because "corona" sounds similar to "kuruma" (meaning "car"), and that's why the "bo" kanji has the "car" kanji in it.
[1] http://jisho.org/kanji/details/暈