Disappeared from the dock or from your Applications folder?
If it is gone from your Applications folder, it would have been dragged to the trash. Look there. For it to be completely gone from your HDD, the trash would have been emptied. Assuming all that happened, I'm pretty sure there's a disc that came with your Mac (never needed to dig mine out of the filing cabinet) that has all the native Apps normally pre-installed.
From the applications folder and dock. I tried searching it at the top but nothing comes up and its not in the trash or nothing. i tried looking for the disc but cant seem to find it at all. anyway to download it?