Range to array, then check to see if the array contains a string

Hey
I'm making a word game.
At the moment I have a large dictionary sorted through columns AA to ZZ. 173000 words. To check if a word is true I get the first 2 letters of the string, which references me to the column. Eg the word help will scan through the column "HE". 1 of the columns "RE" is over six thousand rows, so it takes about a quarter f a second to scan. Ideally I would like it faster.

I know I can scan it faster if I use an array, although I am pretty clueless when it comes to ten.

If I put all the words into column "A" (173000 odd lines) could someone please help me with code to add this column to an array.

Then I wish to check a string variable against the array, and then find out if it's in there.

Everything is done in uppercase so that's not a problem.

Many thanks for your help.