The term jokoto (kanji: 上古刀) means "pre-900 AD swords" in English. It is written じょうことう in hiragana. It may also be rendered in English as joukotou or jōkotō. It's pronounced roughly like "joke oh toe".
Any Japanese swords made up to 900 AD are labeled jokoto. The Jokoto Period is the earliest period of sword production and encompasses the famous Nara Period (710-794) of Japanese history.
古刀, koto, means ancient sword. The prefix 上, jo, literally means upper. By itself, it is pronounced ue: up or above. As jo, however, it has the additional meaning of “coming first” (since the Jokoto Period precedes the Koto Period). In Japan, long novels are often published in two volumes with the first being labeled 上, jo, and the second 下, ge (down or below).