The term nanbokucho (kanji: 南北朝) means "the period 1336-1392" in English. It is written なんぼくちょう in hiragana. It may also be rendered in English as nanbokuchō , nanbokuchou , nanboku-cho , nanboku-chō or nanboku-chou. It's pronounced roughly like "non-bo-koo-choh".
This word, denoting the era in Japanese history spanning from 1336 to 1392, is the exact same word that the Chinese use to denote a period in their own history (the Northern and Southern dynasties, 420-589). The Japanese call the Northern and Southern dynasties by a longer name, though, so there is no chance of confusion.
南 means south; the Chinese reading (for Japanese) is nan, the Japanese minami. 北 means north; the Chinese reading is hoku, the Japanese kita. In this word, “hoku” is pronounced “boku” due to the linguistic phenomenon known as sequential voicing, where (among other things) “h” becomes “b”.
朝 literally means morning, and its Japanese reading is asa. This kanji is used to denote dynasties, apparently due to a custom dating back to the Nara period where the prince would hold conferences and take care of other political matters in the early morning. Its use is not limited to Oriental dynasties: for example, the Victorian era is called ヴィクトリア朝 (Victoria-cho).