Explanation on what some categories contain:
- Arm (Parts) - Contains parts that make up a movable mechanical arm on a robot or a Space/Aquazone vehicle. On the end of the arm is usually a grabber (to grab objects with). Some parts in this category are also used in Homemaker figures to make up the arm (body part) of the minifig.
- Baseplate, Road - Contains only baseplates with studless surfaces that go completely across the baseplate, which are reasonably roadlike in nature and, if not completely undecorated, are decorated with some sort of road, drive, parking, or pad pattern. You shouldn't find here a baseplate with a river pattern even though the baseplate itself can also be found with a road pattern. Terms like 7-Stud and 9-Stud refer to number of studs in the margins of the baseplate, from baseplate edge to pattern start, in a line perpendicular to the road surface. Terms like Narrow and Wide refer to road pattern width and thus indicate how close the pattern is to the studs on either side. So, Narrow means the edge of the pattern falls farther away from the studs and Wide means closer to them. The Narrow version of airport runway type patterns is reported to be the later version, ostensibly to match them to regular road patterns.
- Belville, Clikits and Scala products are geared towards girls.
- Boat (Sets) - Contains only floating boats. Other boats and ships are under their respective themes.
- Cloth - Contains only parts made out of cloth that don't fit in any other category. Other parts made out of cloth can be found in other categories based on whether the parts are worn by minifigs or are theme-specific such as Belville or Scala.
- Dino 2010 was Available in Europe. Dino Attack was Available in USA.
- Factory - The models are created with the LEGO Digital Designer software by independent people.
- FIRST LEGO League - FIRST is an acronym for For Inspiration and Recognition of Science and Technology.
- Legends - Certain old popular LEGO sets re-released as LEGO Legends. This series has been discontinued.
- Legoland Parks - Items that were sold at any of the Legoland Parks only.
- Minitalia - Special series available only in Italy in the 1970's.
- My Own Creation - 3 sets released in 2002 originally designed by AFOLs.
- Value Packs - Are several sets packaged together. Sometimes a Gear item is included in the package.
- Classic Castle - Contains Castle sets released between 1978 - 1983.
- Black Falcons and Lion Knights are made-up names based on the insignia on the shields of the factions in these sets. There was no official sub-theme name for these sets. In 1990, several sets containing shields and figures with the lion insignia have been released and officially called "Crusaders".
- In 2001 - 2003, the only Castle sets released were Legends and one set originally designed by an AFOL (no regular retail sets). This was presumably due to Harry Potter covering the historical portion of regular retail sets.
- Fantasy Era - Starting in 2007, LEGO calls new Castle sets as simply "Castle". Since this would create a conflict with the main "Castle" category, BrickLink has created a category called "Fantasy Era" for these sets. Unlike previous years sets which also included non-human characters, Fantasy Era contains whole factions made out of solely non-human characters such as undead, dwarves and trolls.
Several categories besides town contain Town-like sets including fire, police, etc:
Town sets which do not fall into any of the official Town sub-themes are sub-divided into several main categories:
- 4 Juniors - Jack Stone and 4+ sets also contain town-like sets such as fire, police, etc.
- Building Set with People - These are identified by having this name on the box and also by having large figures.
- Duplo Town - Features similar sets as regular town including fire, police, etc.
- Legoland - Includes only pre-1978 sets with the word "Legoland" on the box, in instructions or in catalogs plus promotional sets from that era. 1978 and newer sets are under Town. Several promotional sets which look more like Legoland sets are under Legoland even though they were released in 1978. The difference between Legoland and Town is also in the minifigs. Town contains minifigs with movable arms and legs which started in 1978 while Legoland contains minifigs with non-movable arms and legs which started in 1975.
Several official Town sub-themes have been omitted. These are: Flight, Nautica, Race, RSQ911, Rescue. Sets in these sub-themes might show in different catalogs under different sub-themes.
- Classic Town - Contains retail Town sets released between 1978 - 1996 without an official sub-theme (*) plus promotional sets released up to 2001 which would fall in the Town Jr. era but were not juniorized.
- Town Jr. - Between 1997 and 2000, Town sets were more simple than traditional Legoland and System Town sets geared towards being more simple to build for children. This movement has been unofficially dubbed as "Juniorization", hence the made-up name of "Town Jr." Sets in this era released between 1999 - 2000 have a "City" logo which is different than the logo on City sets released in 2005 and later.
- In 2001 - 2002, the only Town sets released were promotional, limited release and Legends (no regular retail sets).
- World City - In 2003 and 2004, Town sets were branded with a "World City" logo on a green background.
- City - In 2005, LEGO switched to a "City" name with its own logo.
|Basic and Universal Set Sub-Divisions:|
- Basic - Contains only sets with the word "Basic" on the box or on the front page of instructions.
- Basic Set - Is a boxed set containing basic bricks where there isn't any particular main model.
- Basic Model - Is a set that builds a small main model.
- Classic Basic - Is a set that has a black stripe with the word "Basic" or "Classic" on it.
- Model - Is a set that builds a complex main model.
All of the following categories include sets which contain parts to supplement other sets.
Beginning in 2005 (?), LEGO switched to selling supplementary individual elements through its Pick-a-Brick service.
- Supplemental - Usually available through regular retail and grouped along with other sets in the same theme.
- Service Packs - Usually available only through mail order and shown in back of catalogs in their own section.
- Bulk Bricks - Beginning in 2000, LEGO switched from the Service Packs name to this name.
|Sets for Younger Children:|
Sets for the youngest children were originally released under the LEGO Duplo name. In 1995, the name was changed to LEGO Primo and lasted until 1999. In 2000, the name was changed to LEGO Baby and lasted until 2005.
- Primo and Baby - Sets in the 1-18 months age range.
- Duplo - The size of a Duplo brick is exactly double the size of a regular system brick.
- Explore - Duplo and Baby sets were sold under the name Explore in 2002 and 2003.
- Quatro - Sets in the 1-3 age range. The size of a Quatro brick is exactly double the size of a Duplo brick and quadruple the size of a regular system brick.
- 4 Juniors - Sets in the 4+ age range containing system parts but larger non-system scale minifigs.
- Early Toy - Contains wooden toys manufactured between 1932 and 1960 made before LEGO started to make building sets. Also contains 1:43 Modelbiler vehicles which were a predecessor to the HO 1:87 vehicles.
- Classic - Contains vintage items.
- Parts - Contains bricks with slots and windows and doors for slotted bricks.
- Sets - Contains sets released between 1949 and 1969 with several exceptions: Some 1969 system sets are located in the Legoland category. Train sets released in 1966 and newer are located in the Train category. Sets marketed by the Samsonite corporation (most of which fall into the Classic era) are located in the Samsonite category. Architectural (hobby und modelbau) sets are located in the Architecture category.
- Samsonite - LEGO items marketed in the USA by the Samsonite corporation prior to 1973.