A mortgage broker is the person who holds the actual license to lend in the licensed states. Loan officers are licensed to originate loans under the mortgage brokers license
A job title for a mortgage broker can be loan originator. The loan originator is the person who originates or obtains the financing for your mortgage and in most states has to be licensed.
The lender is the company that actually provides the funds to close your loan. This is different than the mortgage broker and loan officer. The lender is responsible for underwriting the loan and making sure that all of your paperwork adds up. They will then, most often, package the loan with several other loans, and sell them in the secondary market.
Often time your loan officer is also your loan processor, in other words the person who will collect all your documents and make sure all needed conditions are met for a timely funding.
Many loan officers also call themselves 'mortgage consultants'. This is a different name for the same job. In addition, some loan officers refer to themselves as mortgage brokers. This is not accurate. They are not brokers unless they are licensed as such - most loan officers are not.
An Upfront Mortgage Broker, or UMB, will usually charge a flat fee for his service then pass any savings, such as yield spread premium, on to the customer with a broker credit.
An underwriter is the person who scrutinizes the borrowers' credit documents the loan processors prepare. The underwriter's main concern is to ensure the loan files are in compliance with state and federal laws, and that the loan documents satisfy the conditions put forth by the investors on the secondary market.
Mortgage Advisor is becoming common.