northeast同northeastern有咩分別?

'northeast' and 'north-east' are the same. They are both nouns revealing direction.
'northeastern' is an adjective talking about directions.

northeast


n.[theS]
東北; 東北方[U]
The wind blows from the northeast. 風從東北方刮來。
(常大寫)東北部(地區)[(+of)]
(大寫)美國東北部
a. 形容詞
(在)東北的; 朝東北的; 來自東北的[B]
the northeastentrance 東北角的入口
ad. 副詞
在東北; 向東北; 來自東北
At this point the road turns northeast. 路在這裡轉向東北。


northeastern


a. 形容詞
(在)東北的; 向東北的; 來自東北的
(常大寫)東北部的
Heavy floods hit NortheasternIndia.
大洪水襲擊了印度東北部。