I'll bite as well because I think there is something really odd about the original comment about daito ryu and swords.
The word daito in sword parlance simply means, well, large sword. Dai or O (ya know, O-sensei) means "big or large or great". The kanji for To here means "sword". It is often used if you're referring to the large sword in a daisho (meaning long and short sword "set"). So the katana is a daito while the tanto or wakizashi of a set is the sho (or shoto).
My understanding is that daito in Daito Ryu refers to a different kanji entirely for To. Something along the lines of "Great East". Same dai, different to.
Keith, you are quite correct. The "daito" of Daito Ryu is 大東 (great south) while the the other is 大刀 (big sword). 大刀 is a pretty uncommon usage. Usually they go with 太刀(big sword) or just katana 刀. I will add however that usage rules in kanji are a mess, and I don't ever expect to fully understand them.