The Vietnamese word "chữ ký" is a noun that means "signature" in English. A signature is a person's name or a unique mark that they write by hand, usually at the end of a document, to show that they agree with the content or to identify themselves.
While "chữ ký" primarily means "signature," it can also imply the distinctive style or manner in which someone writes their name. This can be used metaphorically to describe someone's unique mark on their work or contributions.