To refer is to point in the direction of a particular thing, or a person mentions another person or a thing:
What is he referring to?
To what is he referring? (This avoids ending the question with a preposition.)
To whom is she referring?
Is she referring to me? (Is she talking about something that includes me?)
What does this word refer to?
The word "aquatic" refers to activities involving water.
A large sign outside of the building refers to the people who built it.
The students at the college refer to their history professor as "Dr. Schmidt." No one calls him by his first name. (Some professors go by the title of "professor.")
You shouldn’t refer to a doctor by his or her first name. (Medical doctors are rarely addressed by their first names inside a doctor’s office or hospital.)
Did you refer to the directions when putting the bike together?
The logo on a product refers to the manufacturer.
This sign refers drivers to the presence of a railroad crossing.
The word "refer" is often used when one person recommends another person for a job. This is called a reference. The word "refer" is also used when a person has a particular area of expertise:
The young woman was referred for the job because she had the necessary skills.
Everyone refers to Jim as an expert in this area.
I’m going to refer you to someone who has more experience with this.
A friend of mine referred me to you. (A friend of mine recommended you because of your expertise.)
The word "referral" is a noun. When someone makes a referral, he or she makes a recommendation. The word "referral" is commonly used in business:
Most of Bob’s new business comes from referrals. (Customers happy with his work recommend him to other people.)
Real estate agents get a lot of business through referrals.
Linda asks her clients to voluntarily fill out a referral form in order to generate new business.
This sign refers drivers to the presence of a railroad crossing.