hey
/heɪ/exclamation
1- used to attract attention, to express surprise, interest, or annoyance, or to elicit agreement（用于吸引注意力, 表示惊讶、兴趣或恼怒, 或诱使同意）嘿, 喂：
hey, what's going on here?
嘿, 这儿发生了什么事？
1.1
- US used as a friendly greeting〈美〉你好：
I just called to say hey.
我打电话给你就是问个好。
短语
hey up
- Brit. Informal used as a greeting or as a way of drawing attention to something〈英, 非正式〉（用于打招呼或唤起注意）嘿：
Hey up, Margaret!
嘿, 玛格丽特！
Hey up! Here's the cops!
嘿！警察来了！
what the hey
- N. Amer. informal used as a euphemism for 'what the hell'.〈北美, 非正式, 婉〉同 what the hell.
词源
natural exclamation: first recorded in Middle English.