A FSBO or unrepresented buyer would be a perfect example of a customer. If you work with them on a transaction, you'll be cooperative and honest, but you will not represent them and you owe them no fiduciary responsibility. You will act in the best interest of your client only. That will be immortalized in writing.

No such thing in my world.

They're either leads, prospects or clients. I don't own a store, therefore I serve no customers.

 We do not have a fiduciary relationship. 

Not a fan of this word for our business. Sounds like retail to me. There are some other good answers!

Someone with whom we discuss our trade/profession, to whom we owe no fiduciary duties.

You have many great answers here.

UNREPRESENTED Consumer

A customer is someone who is not a client with a signed representation agreement. 

Someone who refused to sign my buyer agency agreement and was sent onto work with someone else.

someone who is not yet a client.  I only work for clients.

A person or persons whom you do not have a contractual relationship with, however, they do have a keen interest to purchase, sell, rent or lease real property.

REAL ESTATE CUSTOMER: Those who sleep under a roof. (AL 2017revision 91)

That is not the same as 'My real estate customer."

That is what is good about this business, many agents can define the business they want.

Someone you assist but do not represent.

Anyone you are working with that is not your client.

 Check CA state law for the definition of Real Estate Consumer. I could give you the definition for consumer from PA state law but that would not help you in CA.

It depends on the state agency laws. In Florida almost all buyers and sellers are customers, in Virginia they are clients unless they sign an agreement that you are not representing them.

we represent clients.... listing clients because we are listing agents.... buyer clients when we wear the buyer's agent hat... no customers....

I have not used that wording. I have worked with prospects, clients, home buyers, home sellers and real estate investors. 

A person who is still shopping around with no agent. Once they have an agent they become a client.

Part of me wants to say "ditto" to Thomas J. Nelson, Realtor,CRS,e-Pro's answer, but in the corporate IT world we were always taught that anyone we interact with in a professional capacity is a "customer" of ours.  When I was working in the hospitals you'd think the customers were only those coming in for treatments/tests or the visitors but whenever I did my compliance rounds the entire staff and mainly the department managers were my customers and the product I "sold" was my reports.  When I worked on implementing security controls with the "C level" executives, they were my customers.  When I taught at new hire orientation, the new hires and the education department were my customers.

In a real estate transaction, my clients are obviously my customers.  I am a customer to escrow, title and the other vendors, the other agent is a customer of mine (because we provide them data, forms, etc.).  The person walking off the street into an open house is a customer in some regards and (if you're inviting enough) a customer waiting to happen.

No fiduciary relationship - not a client. 

Non-fiduciary relationship.

As you spelled it. It is a generic term.

Someone interested in purchasing real estate.

Tammy Lankford, nailed this one!

Customer is someone that hasn't yet, or isn't going to commit in writing to becoming a client.

Someone who needs to be qualified as ready, willing and able!

It will be a Buyer who does not have a signed Buyer Representation Agreement with you.  Seller's always have a listing agreemenet signed, so it cannot be them.

No customers here, just clients

RE Customers are not really term we use in SoCal. You are a client or you are not. 

Jesus,

Personally, we do not like the word "customer".  You have some excellent comments to reflect on from the members. A

A client who has bought a property

Usually a buyer with whom you do not have a buyer broker relationship. Not something I would ever look for :-)

My Client???

There will be a difference in Customer and Client....

I have never used that term.

someone who is looking to purchase real estate who is not represented by an agent

The is a potential real estate client.

Good luck.

In CT, there is a legal definition - a customer is someone with whom you do NOT have a contract and owe them no special duties, fiduciary, obedience, etc. A client is one with whom you either have a listing agreement or a buyer agency agreement and you owe him all the duties.

You got 3 types:

client ,traitor or dead beat.

Jesus Henao An individual who is not your client and who you do not have an agency relationship.

A customer is someone who you do not represent, a client has hired you, signed and is now your client

One who has need of a Real Estate service