The word "regarding" means "concerning" or "relating to." It is often used to introduce a subject or to specify what one is talking about. For example, if someone says, "Regarding your question about the assignment," they are indicating that they are going to talk about the question related to the assignment.
The word "regarding" comes from the combination of the prefix "re-" meaning "back" or "again," and "guard" from the Old French "regarder," which means "to look at" or "to consider." The word has evolved to mean "to look at" a particular subject or topic.