Like the World Wide Web that preceded it, the new 3D Web has its own vocabulary. We try to make it easier to keep up.

[anchor id="avatar"]avatar

A representation of a user, usually as a three dimensional cartoon character. Avatars can be realistic, based on actual photos of the user, or fantasy constructs. Some avatars are animals or mythical creatures or robots. Avatars in some worlds are anatomically correct.

On adult-oriented grids such as Second Life, child-like avatars are forbidden.

Avatars are used to communicate with other users via typed text or in-world voice. Depending on the world, avatars can also interact with other avatars by trading goods or money, through physical violence, or with  hugs, handshakes, dancing, and even sexual intercourse.

Avatars can also have property, such as game weapons and costumes. Avatars may be used to own virtual objects and property. In worlds that have currency systems, such as Second Life, avatars are also used to own virtual money. Related articles.

[anchor id="behindthefirewall"]behind the firewall

A grid that is “behind the firewall” is the equivalent of an intranet site — it is only accessible to a limited group of people, such as company employees.

[anchor id="browser"]browser

Software used to access virtual worlds. Common browsers include the official Second Life browsers, Hippo, Meerkat, and Imprudence.  Also referred to as a viewer.

[anchor id="grid"]grid

A grid is a collection of regions arranged like squares on a chess board. The regions don’t have to be adjacent to each other, but when they are, users can walk or fly from one adjacent region to the other. Regions can be solid squares of land, or be partially or wholly covered with water.

If a square on a grid is not occupied by a region, it looks like open water from a distance. However, users can not fly or swim through this water.

[anchor id="hypergrid"]hypergrid

The virtual worlds equivalent of the World Wide Web. When a world is on the hypergrid, it means that users can teleport in and out from other worlds, similar to following hyperlinks to and from different Websites.

“Hypergrid” can also be used as a verb. For example: “Can you hypergrid over to ScienceSim to check out the new Intel conference center?”

See also hypergrid teleport.

[anchor id="hypergridteleport"]hypergrid teleport

Teleportation — or instantaneous travel — between different virtual worlds or grids. Currently, only worlds running on the OpenSim platform are capable of hypergrid teleport. It is technically possible to hypergrid teleport between Second Life and OpenSim, but that is currently not enabled by Linden Lab for business reasons.

[anchor id="immersive"]immersive

A virtual world is immersive when users are able to feel that they are present inside the world. An immersive world usually has fully three dimensional graphics and allows users to see objects from any direction, and to interact with other users and with the environment. Related articles.

[anchor id="inventory"]inventory

An inventory is an avatar’s belongings. Inventories typically contain of clothing, body shapes, furniture and other objects, text files, small programs called scripts, name cards of other avatars, and favorite landmarks.

[anchor id="libopenmetaverse"]LibOpenMetaverse

A set of messaging standards that Second Life and OpenSim servers use to communicate with their browsers. Formerly LibSecondLife. LibOpenMetaverse messages were originally decoded in order to create bots, but were later used as the foundation for the OpenSim and realXtend virtual world platforms. Official site. Related articles.

[anchor id="lindenlab"]Linden Lab

A pioneering virtual worlds company, owners of the Second Life grid and software, and operators of the Linden Dollars, a virtual currency.

[anchor id="lindendollars"]Linden Dollars

A virtual currency interchangeable with the U.S. dollar, used in Second Life transactions. Also known as Lindens, and L$.

[anchor id="opensim"]OpenSim

OpenSim is open source software that runs virtual worlds compatible with all Second Life browsers. It uses the LibOpenMetaverse library to communicate with the browsers, as does Second Life.

[anchor id="parcel"]parcel

A parcel is a subdivision of a region. Parcels can be of any size, and are commonly used when a region owner rents out parts of his region to others to use for homesteading, retail locations, or office space.

[anchor id="persistent"]persistent

A virtual world is persistent when it continues to exist even when no users are using it. Some virtual worlds are created on the fly, for the purpose of a particular meeting or event. Persistent worlds exist independently of any individual event, and continue to run processes — such as nature simulations — even when nobody is there.

[anchor id="portal"]portal

Portals — watery blue disks reminiscent of the StarGate on the SciFi channel show — are often used the indicate the presence of a hypergrid link, similar to the way a blue underline is used to indicate the presence of a hyperlink on a webpage. Portals are usually activated by stepping through them, or by clicking on them. Some portals only go to one destination, while others give the user a choice of destinations. Also known as teleportation portals, stargates and hypergates.


All objects in OpenSim (and also in Second Life) are built out of geometric solids — cubes, spheres, donuts, and pyramids. These geometric shapes are called primitives or “prims.” They can be twisted, stretched, and otherwise manipulated and combined to form any object. By default primitives look as if they’re made out of plywood. By pasting a photograph to the outside — a texture image — a primitive can look as if it was made out of brick, glass, metal, or any other material. A prim object is usually differentiated from a “mesh” object (though technically a prim is a type of mesh) in that mesh objects such as those produced by 3D modeling programs can have dozens — or hundreds or even thousands — of polygons making up their surface, making the objects more detailed.

[anchor id="realxtend"]realXtend

Similar to OpenSim, realXtend is a virtual world server platform and browser system compatible with Second Life browsers and the LibOpenMetaverse messaging library. However, realXtend adds additional functionality in the form of support for full mesh objects, making it possible to import objects from 3D modeling software. As a result, while the realXtend browser can be used to view Second Life and OpenSim worlds, other browsers will not correctly display the mesh objects in realXtend worlds. As a result, realXtend is currently being used only for niche applications, such as architecture. However, Second Life announced plans to add mesh support next year, and OpenSim is expected to follow suit.

[anchor id="region"]region

A region is one 16-acre square on a grid — or 256 square meters by 256 square meters. A region is the smallest unit of land simulated by Second Life, OpenSim and realXtend servers.

[anchor id="script"]script

A script is a small program written in a language understandable by the virtual world platform. The Linden Scripting Language (LSL) is the most common virtual world scripting language. Scripts can be used to make doors that open and close, make pets follow their owners around, automatically translate if other avatars speak a foreign language, and perform many other functions. The OpenSim scripting language, OSSL, is a variant of LSL which includes some commands specific to OpenSim.

[anchor id="secondlife"]Second Life

Second Life is the biggest immersive social virtual world, in terms of land area, numbers of users, and size of the virtual economy. Second Life differs from any of the virtual worlds that came before in that users are able to own the intellectual property rights of objects they created in the world. Today, Second Life has moved beyond its social beginnings and is a popular location for educational institutions, museums and companies looking for a virtual world presence.

“Second Life” typically refers to the Second Life grid, which is composed of nearly 30,000 different regions. There is also a separate grid for teens. Many of the regions are attached to one another, making up a large land mass known as the mainland. Others are grouped into smaller islands in the middle of the ocean.

All Second Life regions run on servers owned and operated by Linden Lab. Individuals and organizations can rent regions or parts of regions directly from Linden Lab or indirectly from virtual real estate developers. Prices for Second Life regions start at around $300 a month, plus a $1,000 setup fee.

[anchor id="secondlifeenterprise"]Second Life Enterprise

Second Life Enterprise is a version of the Second Life server software that can run on your own computer. companies can use Second Life Enterprise to create a virtual world that runs behind the firewall. Prices for the Second Life Enterprise software start at $55,000, which includes the ability to run eight regions at the same time. Official site. Related stories.

[anchor id="server"]server

A virtual world server is a virtual world application running on a desktop computer, on a physical server, on a virtual server, or in cloud computing environment such as Amazon EC2.

The most common such applications are Second Life Enterprise, OpenSim, and realXtend. Other virtual worlds platforms include Blue Mars, Wonderland, Collada, and Fortrera.

[anchor id="sim"]sim

A sim, short for simulation, is often used to mean a single region on a virtual world grid.

It is also used to refer to all the regions running under a single instance of a virtual world server application. For example, the OpenSim software can simultaneously run several regions at once.

[anchor id="texture"]


A texture is an image, usually 512 by 512 pixels, which is used to cover the outside of an object to make the object appear to be made of a particular material. Common textures include wood, glass, metal, and stone. Textures are also used in the creation of clothing and hair, and even avatar skins.

[anchor id="viewer"]viewer

Software used to access virtual worlds. Common viewers include the official Second Life browsers, Hippo, Meerkat, and Imprudence.  Also referred to as a browser.

[anchor id="virtualmoney"]virtual money

Virtual money or virtual currency is money which is used inside a virtual world. Examples of virtual currencies include the gold coins popular in role playing games, and Linden Dollars in Second Life.