I once had a friend who told me a story about when her parents decided to build a house in an old fruit garden. Like sensible people they removed the trees, of course, but the two of us would lament the fact that she didn't grow up in a house built around a giant pear tree.
You know, learning Japanese wouldn't be so hard if the kanji (Chinese characters) had only one or maybe just two different pronunciations. But one thing that makes it at least easier to decipher a sentence is that the meaning of the character usually stays the same or close, even if they sound like fifteen different words.
外 means "outside, other place, exterior" and is unfortunately a bit iffy when it comes to its etymology - I've read several different versions but it basically comes down to this:
夕 means "moon", and 卜means "divination". And divination is something done outside, under the moon, hence the meaning "outside".
But if anyone out there knows better, please tell! :)