1. Adverb (fukushi), Adverb taking the 'to' particle

   with a screech; with a whine; with a shrill; with a ringing (in the ears)

   Onomatopoeic or mimetic word

   上空をジェット機がキーンという音を立てて飛んでいった。

2. with a sharp pain (in the head or teeth after eating or drinking something cold); getting a brain freeze

   Onomatopoeic or mimetic wordsee アイスクリーム頭痛

Also written きーんkiin、きいんkiin