Definition of hear of
: to be aware of the existence of (someone or something) : to know about (someone or something) He's supposed to be a famous actor, but this is the first time I've ever (even) heard of him. I've never heard of such a thing! If I hear of a job opening, I'll let you know.
Seen and Heard
What made you want to look up hear of? Please tell us where you read or heard it (including the quote, if possible).