Many Japanese katakana words end in a long sound that is sometimes optional.
For example, パーティー and パーティ are both perfectly valid for "party". Similarly we have センター and センタ that are variants of "center" as well as サーバー and サーバ for "server".
I'm proposing that we add a katakana stemmer that removes this long sound if the terms are longer than a configurable length. It's also possible to add the variant as a synonym, but I think stemming is preferred from a ranking point of view.