This kanji is pronounced だいだい, and I bet you can figure out the meaning pretty easily if I give it to you in this set: 赤, 橙, 黄, 緑, 青, 藍, 紫.
Get it yet? No? Give those another quick look.
Yup, it’s the kanji for orange. You see it infrequently, almost always written. So yeah, supposedly it’s pronounced だいだい色(いろ), but I wonder if people just read it オレンジ. Can any native speakers confirm? 橙 is generally used as the color in the rainbow, but Wikipedia also tells me it came from the Chinese fruit the daidai…which looks like a mikan, except the English name is bitter orange? I’m keen to try one.
The other cool kanji in there that you might not know is 藍(あい), which is indigo. Wikipedia Japan says that Americans generally think the rainbow only has six colors, but I can personally confirm that is bogus. Clearly Wikipedia Japan hasn’t met Mr. Roy G. Biv – that’s the acronym I learned in elementary school to keep the colors straight.