AFOL
    Adult Fan of LEGO. The most common term used to refer to LEGO fans who are adults. Generally pronounced to rhyme with “hay-foal.” See also ALE and ALH.

ALE
    Adult LEGO Enthusiast. Some LEGO fans prefer to be called enthusiasts rather than fans, attempting to avoid the perceived stigma of the word “fanatic.” See AFOL.

ALH
    Adult LEGO Hobbyist. Another alternative self-descriptive name preferred by some LEGO fans over AFOL or ALE

Bandwagon
    A passing LEGO fad, such as cave racers or IATTAR.

Bignette
    A LEGO scene on a defined base that is larger than a vignette. See also Diorama.

Brick-Built
    A LEGO creation or portion of a larger creation that is composed of multiple LEGO elements even when a larger, pre-fabricated LEGO element or custom accessory may be available. Solving a LEGO problem through brick-built means is generally respected more than using a prefabricated or custom element.

BURP
    Big Ugly Rock Piece. A large, pre-fabricated LEGO element generally available in gray and frequently included in LEGO castle sets. More experienced LEGO fans often encourage other builders to use brick-built landscaping rather than BURPs.

Cheese Slope
    A LEGO element with a 33° slope, 1 stud by 1 stud wide and two plates high (or 2/3 of a brick high). Part number 50746. Useful for adding fine detail to LEGO creations. Named after the fact that yellow and orange pieces look like a wedge of Cheddar cheese.

Custom
    A LEGO creation or individual element that uses non-LEGO parts or modified parts, including decals, paint, or accessories from third-party vendors like BrickArms, BrickForge, and Big Ben Bricks. Contrast with Purist.

Dark Ages
    That period in a LEGO fan’s life when he or she sets aside LEGO in favor of school, dating, motor vehicles, and other non-LEGO pursuits.

Diorama or Dio
    A large LEGO scene or a LEGO scene built on an irregular base. See also Bignette and contrast with Vignette.

Half-Stud Offset
    A building technique that allows a LEGO fan to build without regard to the standard alignment of studs on a plate. See also Jumper Plate

Greebles
    Pseudo-technical detail added to a LEGO creation to enhance its appearance. Frequently seen in LEGO space and mecha creations.

Illegal
    LEGO building techniques that break the “rules” for connections between LEGO elements used by official LEGO set designers — particularly connections that stress the LEGO elements. For example, inserting a plate between the studs on a brick.

Jumper Plate
    A 1×2-stud LEGO plate with only 1 stud in the center. Useful for half-stud offset building.

KFOL
    Kid Fan of LEGO. The LEGO Group’s primary target demographic — boys aged 5-12. Most online LEGO fan sites do not allow participation by KFOLs due to COPPA regulations.

Legal
    LEGO building techniques that follow building guidelines for official LEGO set designers. See also Illegal and Purist.

LUG
    LEGO Users Group. Initially used to describe a local or regional LEGO club that met and interacted primarily in an offline or “real world” context, the term LUG has been extended to include virtual and even ephemeral groups of LEGO fans, such as JLUG, ChiefLUG, and KiethLUG. Many LUGs now also have an online presence, further blurring the line between traditional LUGs and online LEGO fan communities.

MOC
    My Own Creation. Any LEGO creation designed and built by a LEGO fan without instructions. Generally pronounced “mock.”

MOCFodder
    A set that you buy strictly for the pieces, rather than because of the set design. The pieces are meant to feed your MOC building, hence the name “MOCFodder”.

MSRP
    Manufacturer’s Suggested Retail Price. The official price for a LEGO set as established by the LEGO Group for a particular market. Individual retailers may set their own prices higher or lower than MSRP, and MSRP may vary from country to country. See also TRU and S@H.

Parts Pack
    An official LEGO set that has many desirable LEGO elements but which may not have an overall design that appeals to adult LEGO fans. See also ISD.

Purist
    A LEGO creation that does not include any customizations, such as decals, modified parts, or custom accessories from third-party vendors like BrickArms, BrickForge, and Big Ben Bricks. A form of religious fundamentalism. Contrast with Custom.

S@H
    LEGO Shop at Home. The old name for The LEGO Group’s direct-to-consumer sales channel, particularly the printed catalog and telephone service. Now also used by long-time fans to refer to the LEGO Shop online. These direct channels are often the only place to ensure that you pay MSRP.

Rainbow Warrior
    The type of multi-colored LEGO creations that we all built when we were eight years old.

SHIP
    Significantly Huge Investment in Parts. A very large LEGO creation — particularly a LEGO space creation. As used in the LEGO space fan community, a SHIP is generally at least 100 studs long.

Sigfig
    The minifig version of a LEGO fan that he or she uses in online communities as an avatar, from “signature minifig.” Sigfigs may or may not resemble the person physically, as LEGO fans used to interacting with each other online discover at LEGO conventions.

SNOT
    Studs Not On Top. A building technique that places LEGO elements on their sides or even upside down to achieve the shape or structure the builder wants in their creation.

Swooshable
    A quality that allows a LEGO creation to be picked up and flown around a room as the builder makes flying noises.

TFOL
    Teen Fan of LEGO. LEGO fans who may be past the primary target demographic for LEGO sets, and who are likely avoiding their Dark Ages.

TLC
    The LEGO Company. See TLG.

TLG
    The LEGO Group. The privately held parent company for all LEGO-related brands and companies worldwide.

TRU
    Toys ‘R’ Us. Though roundly criticized by LEGO fans for inflated prices, Toys ‘R’ Us frequently has LEGO sets earlier than any other retailer (including LEGO) as well as a broader selection than most. See also MSRP.

UCS
    Ultimate Collectors Series. An irregular series of large LEGO Star Wars sets designed for older builders. Frequently used as a scale reference for LEGO fan creations that are larger than minifig scale. See also ISD.

Vignette or Vig
    A small LEGO scene, usually built on a base 8 studs long by 8 studs wide. Contrast with Bignette and Diorama.