The word `nook’ rhymes with `hook’, `book’, and `cook’. Since the 14th century, the word has been used to refer to a remote corner or secluded spot. The `a’ in `cranny’ is like the `a’ in `apple’, `ant’, and `add’. A `cranny’ is a crack or an opening of some kind — for example, a crack in the wall can be referred to as a `cranny’. When you say that you have looked for something in every nook and cranny, what you mean is that you have looked for it everywhere.
*The children looked for the ball in every nook and cranny, but they couldn’t find it.