In real estate, what does 'MLS' stand for?

In real estate, MLS stands for Multiple Listing Service.

An MLS is a cooperative database and set of professional services used by real-estate brokers to share property information. A listing broker enters details under an agreement with a seller, allowing other participating brokers to find the property and potentially represent a buyer.

The system is more than a public property-search website. MLS organizations support broker-to-broker cooperation, offers of compensation, market analysis and appraisals. Access, rules and data fields vary by region, because MLSs are generally operated by local or regional real-estate organizations rather than one worldwide central database.

People sometimes confuse an MLS with a listing portal such as Zillow or Realtor.com. Those websites may display MLS-sourced information, but the MLS itself is the professional data-sharing network behind many listings. The abbreviation can occasionally be expanded as “multiple listing system” or “multiple listings service,” but “Multiple Listing Service” is the standard answer for this question.