I don't consider an array of about 275,000 items to be that big; "big" is on the order of millions, not a couple of hundred thousand.

You need to provide some more information, such as are the words expected to be unique, are your searches case-insensitive, are regexen required, how often does this need to be done, etc. I seem to remember Jon Bentley did something akin to this in his book, Programming Pearls. I believe he was building a word list for a spell-checker. I can't remember the exact form of the data structure he used, so I'm not going into further detail.

fixed markup