Hat tip is (often abbreviated to "HT" or "h/t" in online contexts) used as an acknowledgement that someone has brought a piece of information to the writer’s attention, or provided the inspiration for a piece of writing.

Hat tip在网络语境中表示“致敬，感谢”，缩写为HT或h/t，感谢某人让作者注意到某些信息或者激发了作者创作某个作品的灵感。

Originally, a hat tip is an act of tipping or doffing one's hat as a cultural expression of recognition, respect, gratitude, greeting, or simple salutation and acknowledgement between two persons.

Hat tip最初指两个人见面时通过摘帽的动作来表示对彼此的认可、尊重、感激、问候，或是简单的致敬和感谢。

For example: 

HT to Chris Johnson, who alerted me to the story. 

向克里斯·约翰逊致敬，是他启发了我这个故事。