What is the meaning of 東北?

northeast

(~地區) Northeast China (a region of China; consisting of Liaoning, Jilin and Heilongjiang, and sometimes the northeast part of Inner Mongolia)

(大行政區, ) Northeast China (a former greater administrative region of China from 1949 to 1954, consisting of Liaodong, Liaoxi, Jilin, Heilongjiang, Songjiang, Rehe and Suiyuan, Shenyang, Lüda, Fushun, Anshan and Benxi)

Manchuria

(地方) Tōhoku (a region of Japan)

northeast

Tōhoku (a traditional region of Japan, specifically the northernmost six prefectures in Honshu (clockwise from the northermost): Aomori, Iwate, Miyagi, Fukushima, Yamagata and Akita)

hanja form of 동북 (northeast)

chữ Hán form of đông bắc (northeast)

Source: wiktionary.org