Middle Korean

from The American Heritage® Dictionary of the English Language, 5th Edition.

• noun The Korean language from about 1000 to 1600.

from Wiktionary, Creative Commons Attribution/Share-Alike License.

• proper noun Korean in the 10th century to 16th century, or from the era of Goryeo to the middle of Joseon, based on the dialect of Kaesong because the new Goryeo dynasty moved its capital city to northern area of Korean peninsula.