LEGO® Part Names—the Basics

Pick up a single LEGO® piece and the simplest question may be harder than it sounds: what, exactly, do you call it?

“Piece” works perfectly well in ordinary conversation. The LEGO Group itself commonly uses element as a more formal term for an individual LEGO® building piece. But once you start building, sorting, collecting—or trying to find one particular piece among thousands—the vocabulary quickly becomes more precise.

Brick, Plate or Tile?

The easiest place to start is with the basic shapes.

A brick is the familiar building element most people picture when they think of a LEGO® piece. Its size is usually described by counting the studs on top: a 2×4 brick is two studs wide and four studs long.

A plate follows the same system but is one-third the height of a standard brick. Stack three ordinary plates and you have the height of one brick.

A tile is similar in height to a plate but has a smooth upper surface rather than the usual field of studs.

From there, the vocabulary expands quickly: slopes, wedges, arches, round bricks and plates, modified bricks, clips, brackets, hinges, Technic elements and many more.

The names are practical. They describe enough about a piece’s shape, dimensions or function that another builder has a reasonable chance of knowing what you mean.

Collector catalogs can take this considerably further. BrickLink, for example, generally builds its part names from the type of part, its dimensions and then whatever additional description is necessary to distinguish it from similar pieces.

That’s how you eventually get names considerably more specific than “that little gray piece with the clip.”

From Names to Numbers

Names work well for people. A catalog containing thousands of different designs needs something more precise.

That’s where identification numbers come in.

The LEGO Group uses a Design ID to identify a particular design. In simple terms, it identifies the physical design rather than one particular color of it.

Same design, different color. These two 2×6 plates are different colors, but both have 3795 molded into the underside. The Design ID identifies the design of the element, not its color; the specific design-and-color combination is identified separately by an Element ID.

Take perhaps the most recognizable LEGO® element of all: the classic 2×4 brick, associated with Design ID 3001.

But suppose you don’t just need a 2×4 brick. You need that piece in a particular color.

Now another number becomes useful: the Element ID.

An Element ID identifies a particular design-and-color combination. Consequently, two pieces sharing the same basic design can have different Element IDs because they are different colors.

So our description has progressed:

piece → brick → 2×4 brick → Design ID → specific design-and-color combination → Element ID

Each step simply describes the object more precisely.

Then There Is BrickLink

For collectors, builders and sellers, BrickLink adds another layer of terminology.

In the BrickLink catalog, Part is an item type. Parts sit alongside other catalog item types such as sets, minifigures, books and gear.

Each catalog item receives an Item No. For parts, the BrickLink number often corresponds to a LEGO Design ID—but not always. BrickLink explains that differences can arise because its catalog may account for mold numbers, decorated pieces, assemblies, dual-molded pieces and alternate designs differently from the LEGO Group’s own system.

BrickLink also recognizes the LEGO Element ID, which identifies the particular part-and-color combination. And BrickLink maintains its own color system, whose color names and identifiers do not always match the LEGO Group’s terminology exactly.

So a LEGO catalog and a BrickLink listing can describe the same physical object somewhat differently without either necessarily being wrong.

What About Printed Parts?

Decoration makes things more interesting.

Consider a standard minifigure head. The familiar basic head design is associated with 3626. But knowing that you have a 3626-shaped head doesn't tell you whose head—or even which face—you are holding.

One might have a simple smile. Another might have glasses, a beard or freckles. Still another could have two different expressions printed on opposite sides.

The underlying shape may be essentially the same. The decoration is what distinguishes them.

BrickLink therefore uses more specific catalog numbers for printed parts. When identifying minifigure heads, for example, you will frequently encounter numbers in forms such as:

3626pb####

The additional notation distinguishes particular printed designs in the BrickLink catalog. It is important to understand that this is BrickLink catalog nomenclature, not simply a longer LEGO Design ID.

The same idea applies to other decorated pieces, particularly minifigure torsos. Hundreds of torsos may share the same fundamental physical form while their printing makes them distinctly identifiable catalog items.

For anyone sorting loose minifigure parts, this distinction quickly becomes useful. Knowing that something is a standard minifigure head doesn't get you very far. The face—the eyebrows, beard, glasses, expression, scars and other printing—may be precisely what allows you to identify it.

Our progression can therefore go another step:

piece → type → dimensions → design → color → decoration

The more precisely you need to identify something, the further down the chain you go.

And Sometimes the Number Isn’t the End of the Story

Pieces also change.

A familiar design can be revised as the LEGO Group changes molds or manufacturing details. BrickLink recognizes mold variants and situations in which LEGO Design IDs and BrickLink Item Nos. diverge because of mold numbers or newer designs.

The classic 2×4 brick is a particularly good example.

The modern LEGO® brick dates to 1958, when the now-familiar stud-and-tube principle was patented. LEGO bricks made according to that system have remained compatible across generations, even as details of individual designs and manufacturing have evolved.

Look at two 2×4 bricks from above and they may appear essentially identical. Turn them over, however, and differences in their internal construction or mold details may reveal that they came from different periods.

For most builders, those distinctions don't matter. The brick does its job.

For someone identifying older LEGO® elements, replacing a particular element, cataloging a collection—or sorting a large quantity of used LEGO® pieces—they sometimes do.

A Quick Reference

None of this means you need to memorize a catalog before opening a LEGO® set.

Start with brick, plate and tile. Learn how dimensions are described. From there, Design IDs, Element IDs and catalog numbers provide increasing levels of precision when you need them.

And once we know what all these pieces are called, we can tackle the next question:

How do you sort them?