Dead Mall: A mall with a high vacancy rate, low consumer traffic level, or is dated or deteriorating in some manner. For purposes of inclusion on this site, Deadmalls.com defines a dead mall as one having a occupancy rate in slow or steady decline of 70% or less.

Wikipedia, the online encyclopedia, has a good definition of dead mall.

Anchor: A large store in a shopping center, usually is a highly visible store that is a destination for shoppers. Anchors help draw consumer traffic to a mall.

Outparcel: A store that is not connected a plaza or mall, but is located on the premises.

Primary Store: Usually a store that belongs to part of a large regional or national chain. A primary store usually will construct it's own format storefront when it moves into a mall. You can find primary stores in most thriving malls.

Secondary Store: A store that moves into an existing retail space in a mall, they usually aren't a chain store, but more of a mom and pop location. These stores use existing storefronts, and usually are filling space in an otherwise dead mall.

Redevelopment: To change the architecture, layout, decor, or other component of a shopping center to attract more renters and draw more profits. Sometimes redevelopment can involve a switch from retail usage to office or educational usage of a building.

Mallmanac: A map which lists names of stores and diagrams the layout of a mall. This word is a Sniglet, which is "a word that should be in the dictionary, but isn't".

Kiosk: A store located in the common area of an enclosed mall.

Labelscar: Fading or dirt left behind from a sign on or in a mall. Labelscars leave a readable marking, which is very helpful when identifying former stores.
(The term "labelscar" was brought to the forefront by Peter Blackbird in 1998 and is now widely used to describe this phenomenon)

Sealed: When a mall is locked up, and closed to the public

Shuttered: When a mall is boarded up.

Enclosed: A mall with a common space or non-retail area that is part of the structure, which joins the stores. Usually the space is climate controlled, and has places for kiosks.

Open Air: A shopping center in which stores are only accessible via exterior entrances.

Big Box: A large store that deals in volume.

Category Killer Another term used to negatively describe a "Big Box", referring to the results when a Big Box opens opens and an entire category of Mom & Pop stores and/or small retailers in that category go out of business.

Ancillary Mall: A mall that has been supplanted by another shopping center, but is surviving as an alternative to the dominant mall.

Greyfields: malls where annual sales per square foot is less than $150, or one-third the rate of sales at a successful mall. (this term is used to describe dying malls and was coined by PricewaterhouseCoopers (PWC) and the Center for the New Urbanism after the term "brownfields": old industrial sites).

Arcade:

1. A store space containing only pinball machines and video games. Popular in malls in the '70s and '80s.
2. Name often given to an enclosed section of an otherwise open-air shopping center.
3. An early form of shopping mall, dating from the 1900s, where one or two floors of retail occupied the ground levels downtown office buildings.