LDraw Part Naming Styleguide

[tom alphin]

As many of you know, I've been working on an online LEGO Parts Guide as part of my brickarchitect.com website.  I have recently announced that I am planning to turn it into a printed book as well, which I hope will become a valuable resource within the LEGO Community.

One of my goals in refining the online guide and preparing it for a print edition is to ensure my part naming strategy is thoughtful, consistent, and aligned with terms used throughout the community.  It's also important to recognize that the shorter part names I use are not meant to be used in isolation, but rather to always be shown next to an image of the part.  (The website also allows me to define a longer version of the name which helps with search functionality.)

In order to create consistent naming conventions, I recently prepared a first draft of the glossary, abbreviations, and naming conventions I will be using in the guide. 

I wanted to share it with this group for two reasons:

1. I would genuinely love your feedback on the approach I'm taking.
   
2. I wonder if there is a similar styleguide for naming parts on LDraw.  (If not, maybe this document would be a helpful starting point in creating one.)
   

Feedback encouraged and genuinely desired!

Sincerely,
---Tom Alphin

--------------------------------------

Glossary
Ø (Diameter) – Describes the diameter if a curved element was a complete circle/sphere.
Arch – Part with downward-facing curve relative to vertical axis.
Bar – Part with cylindrical section that can be grabbed by a clip or minifigure hand.
Baseplate – Very thin and slightly flexible part with studs on top, most commonly currently used in the Modular Building Series.
Bracket – SNOT piece which has an ‘L’ shape, usually with a plate thickness section oriented with studs facing upwards, and a vertical section with studs facing outwards.
Brick – The basic building blocks of LEGO have studs on the top and are multiples of 8mm wide and 9.6mm tall when stacked.
Corner – Part which have a section removed on the horizontal axis.  This missing area could be a rectangular area, at an angle, or curved.
Cutout – A rectangular area missing from side or bottom of part.
Door – Part which rotates around vertical axis.
End(s) – Describes one or both ends of a part.
Frame (Door Frame) – Part with large outward-facing opening for door or large window.
Handle – A Bar that is closed on both ends.
Horizontal – Something is lying on the ground. Also described as parallel to the earth (horizon).
Nose – Part which is angled in both horizontal and vertical axis. (Sometimes described as a Wedge Slope.)
Recessed – A rectangular area missing on vertical axis which still has studs.
Rock – Part with irregular and rough appearance.
Pane – Part which inserts into a Window, including transparent parts (Glass) or a lattice/grille pattern.
Panel – Part with a thin wall instead of a full brick wide.
Plate – Part which are 1/3 of the height of a LEGO Brick.
Slope – Part which has an angled section relative to vertical axis.
SNOT (Studs Not On Top) – Parts with studs facing outward (horizontal axis) instead of just on the vertical axis.
Tile – Part with a smooth top surface (in the vertical axis).
Vertical – The way that classic LEGO bricks are stacked.  Also described as up/down.
Wedge – Part with angled section relative to the horizontal axes.
Window (Window Frame) – Part with an outward-facing opening in the vertical axis.
Windscreen –Panel thickness part which is angled on vertical axis, usually used in vehicles or spaceships.

Abbreviations
Abbreviations are used as needed to keep part names shorter for part labels and names shown in this book.
L. (Left), R. (Right), Inv. (Inverted), Dbl. (Double), w/ (with), D. (Diameter), ID. (Inner Diameter), Pos. (Position Sensor), Sm. (Small), Med. (Medium), Lg. (Large), XL (Extra Large).

Part Naming Conventions
Part names in this guide are shorter than the names used by The LEGO Group or other LEGO-related websites.  These shorter names are easier to remember and save space.  They are not meant to be a thorough description of each part; but rather to complement the part image by providing clarifying details and relevant terminology. Where possible, I use the terminology in this glossary to describe each part.
If you want to learn more about a part in this guide, visit brickarchitect.com/parts and search for the part number listed beneath each part.

Criteria for Inclusion
This guide aims to include all ‘common’ parts which are currently being produced.  In practice, this means the top 2000 parts which were produced in between 2020-2024 based on a weighted ranking system.  Some parts are excluded due to the lack of 3d models required to create custom images. Many additional parts are included in the guide beyond the top 2000 parts, including a selection of useful parts which were released in 2025, and rare parts that are important for the completeness of the guide (such as a complete selection of current electronics).

[David Manley]

<snip>
Bracket – SNOT piece which has an ‘L’ shape, usually with a plate thickness section oriented with studs facing upwards, and a vertical section with studs facing outwards.
</snip>

Hmmmm, not all brackets are "L" shaped. Consider:

https://library.ldraw.org/parts/7997

and

https://library.ldraw.org/parts/389

David

[tom alphin]

Hmmmm, not all brackets are "L" shaped. Consider:
https://library.ldraw.org/parts/7997 (Part #41682)
and
https://library.ldraw.org/parts/389 (Part #11215)
David

Great examples, thanks for pointing them out.  I think 41682 might still count as a bracket in my mind, but 11215 and related vehicle 'brackets' make me wonder if a different term should be used for these vehicle parts from the SNOT brackets.

I did just edit my copy of the glossary to say "usually has an ‘L’ shape" based on your feedback, thanks for providing specific examples!

---Tom

[Willy Tschager]

Arch – Part with downward-facing curve relative to vertical axis.
Corner – Part which have a section removed on the horizontal axis.  This missing area could be a rectangular area, at an angle, or curved.

I'd say an arc is a brick missing something at the bottom, basically a rotated corner, while I'd say a corner is missing something on the vertical axis.

Nose – Part which is angled in both horizontal and vertical axis. (Sometimes described as a Wedge Slope.)

Never ever heard of a "Nose" just "Wedge" or "Wedge Plate".

Slope – Part which has an angled section relative to vertical axis.

Can also be rounded.

w.

[N. W. Perry]

Part of the question is whether you intend to describe form or function, and I think few would argue that form is really what you're interested in: that is, the actual shape of a part, rather than how it's used, because the latter is endlessly variable.

The problem is that many of the proposed terms have intrinsic meanings of function. For example, an arch has a particular structural purpose, which is derived from and relative to its shape, but there are certainly parts that have arch-like shapes that are coincidental to their possible function as arches. Some of these might be currently classified as "bow" or "mudguard" or similar terms.

"Corner" is another example: the original corner piece was the 700H corner brick, basically two 2x4 bricks fused at a right angle. Over the years, this gave rise to a number of other parts whose use may have been originally "intended" as corners, but also any number of other parts whose use as such may be incidental.

I guess what I'm getting at is that, since you're describing form, you'd want to avoid terms the connote function. However, this is hard to do because almost every new element does have some kind of original, intended function; furthermore, the element's form can often be described far more intuitively using a functional label, but this doesn't always apply to every element that fits into the same category with respect to its form. To really have a comprehensive system of nomenclature, you have to have a non-trivial consideration of the history of the system as a whole; otherwise you end up with terminology so dry and empirical that it isn't really any more descriptive than pure element numbers.

[Magnus Forsberg]

Windscreen –Panel thickness part which is angled on vertical axis, usually used in vehicles or spaceships.

There are a number of flat, non-angled windscreens.

30161, Windscreen  1 x  4 x  1.333 Bottom Hinge
64453, Windscreen  1 x  6 x  3
65735, Windscreen  1 x 10 x  4
19212, Windscreen  1 x 12 x  4 Trapezoidal
80573, Windscreen  1 x 14 x  6 Trapezoidal
4594, Windscreen  2 x  4 x  2 Vertical

[N. W. Perry]

There are a number of flat, non-angled windscreens.

30161, Windscreen  1 x  4 x  1.333 Bottom Hinge
64453, Windscreen  1 x  6 x  3
65735, Windscreen  1 x 10 x  4
19212, Windscreen  1 x 12 x  4 Trapezoidal
80573, Windscreen  1 x 14 x  6 Trapezoidal
4594, Windscreen  2 x  4 x  2 Vertical

And there are a lot of windscreens indistinguishable from what this guide calls "nose" (aside from being transparent).

[tom alphin]

Part of the question is whether you intend to describe form or function, and I think few would argue that form is really what you're interested in: that is, the actual shape of a part, rather than how it's used, because the latter is endlessly variable.

The problem is that many of the proposed terms have intrinsic meanings of function. For example, an arch has a particular structural purpose, which is derived from and relative to its shape, but there are certainly parts that have arch-like shapes that are coincidental to their possible function as arches. Some of these might be currently classified as "bow" or "mudguard" or similar terms.

...

I love how you framed this comment/question, and you are right that I am much more concerned with Form than Function because LEGO builders are a very creative group, and I want to help people find the part that has the shape needed to solve problems in their project.

As for the example of an Arch, I would probably feel comfortable describing something as an arch if it has that shape, even if the studs weren't in the right configuration to create a strong arched structure.  That said, I am currently describing curves on different axes using different words, even though builders can change the orientation using SNOT techniques.


There is an exception however, and that's Technic - within that section I try harder to organize parts by function because Technic really is a different building system with a different underlying grid and philosophy.


I will likely incorporate some clarification around form-first vs. function-first sorting and naming conventions into the narrative.  This was very helpful, thank you.

[tom alphin]

There are a number of flat, non-angled windscreens.

30161, Windscreen  1 x  4 x  1.333 Bottom Hinge
64453, Windscreen  1 x  6 x  3
65735, Windscreen  1 x 10 x  4
19212, Windscreen  1 x 12 x  4 Trapezoidal
80573, Windscreen  1 x 14 x  6 Trapezoidal
4594, Windscreen  2 x  4 x  2 Vertical

I am personally inclined to call it a panel if it is vertical, and windscreen when sloped.  That said, you raise a good point and I will revisit the naming for these parts!

[Peter Blomberg]

Nice of you to share this with us.

What you describe is a _part classification system_ based on _tags_.
You have decided to emphasize _form_ over _function_.

You will want to avoid overlapping tags as they enable ambiguity.
Remove 'arch' because every arch is an inverted slope used for a particular structural function.
Remove 'windscreen' because every windscreen is a wedge or a panel used for a particular function.
Remove 'handle' because it describes a particular function of a 'bar'. The grabbing function is already included in the definition of 'bar'.
Merge (door) frame with (window) frame and remove the explicit reference to an insert.

Does 'door' exclude panes in door frames?
What is a 'door' but operates on a vertical axis? Many hinge parts and rear door of car.
Is a vertical hinge a 'door'?

The glossary appears to be missing cylindrical and conical parts.

Don't confuse size descriptors with form descriptors.

You'll have to resolve the following ambiguities:
Is a 2M x 2M x 1p piece having two studs on top a 'tile' with two studs on top or a 'plate' without two studs?

SNOT is a building technique that uses parts having studs in perpendicular and/or opposite arrangement. You may consider these key pieces to be plate brackets and solid/brick brackets.

Your 'corner' definition needs improving. Perhaps you mean pieces having corner cutouts?

Your 'plate' definition needs improving. A plate can mean the height or it can mean a type of brick. You should separate size descriptors from shape descriptors.

Consider carefully which tags may be modified by other tags.
A 'slope' could be defined as a piece having a narrower top compared to its bottom.
An 'inverse slope' could be defined as a piece having a narrower bottom compared to its top.

'Horizontal' has the wrong description. You must couple the definition to the definition of vertical. The best approach would be to separately define your coordinate system having different modular heights and widths.
'Horizontal' and 'vertical' could be modifiers to 'bar'.

Your 'wedge' definition needs improving to distinguish it from pieces with corner cutouts.
Corner slope or corner wedge?

Add 'curved' to the glossary as a modifier.

Perhaps something like this?
Type - Term - Description - Acceptable modifiers
piece - Baseplate - Very thin and slightly flexible rectangular support with grid of studs on top -
piece - Frame - Part with large outward-facing opening, typically for door or window - Rounded, Corner
piece - Panel - Part with a thin wall instead of a full brick wide - Curved
piece - Bracket - Piece having studs in perpendicular and/or opposite orientation - Plate, Brick, Inverted
piece - Slope - Part which has an angled section relative to vertical axis. - Rounded, Inverted, Curved
piece - Wedge - Part with two or more angled sections in the horizontal plane - Rounded, Curved, Inverted
piece - Brick - Rectangular part having standard modular dimensions - Round, Curved
piece - Plate - Part which is 1 or 2 thirds of the height of a LEGO Brick - Rounded, Round, Curved
piece - Pane - Part which inserts into a Frame, including transparent parts and lattice/grille structures - Curved

modifier - Round - Part having a vertical rotational axis of symmetry -
modifier - Curved - Sloped section having a visible curvature or curvature in horizontal plane -
modifier - Rounded - Edge shape of section as viewed from the top -
modifier - Inverted - Shape where the vertical axis has been reversed compared to the default direction -
modifier - Vertical - The way that classic LEGO bricks are stacked.  Also described as up/down and top/bottom -
modifier - Horizontal - Direction perpendicular to vertical -
?- Recessed - An area lower than the other sections of a part -

subtype or location - End - End of part or part to be placed at the end of some superstructure -
subtype or location - Corner - Corner of part or part to be placed at the corner of some superstructure -
subtype or location - Right - Right-handed version, right side of part, or part to be placed on the right side of some superstructure -
subtype or location - Left - Left-handed version, left side of part, or part to be placed on the left side of some superstructure -
 
accessory - Cutout - A rectangular area missing from side or bottom of part. - Rounded
accessory - Clip -  - Horizontal, Vertical
accessory - Stud -  -
accessory or piece - Bar - Cylindrical section that can be grabbed by a clip or minifigure hand -
accessory - Hinge -  -
 
part - Cone - Rotationally sloped cylinder - Inverted
part - Rock - Part with irregular and rough appearance -
part - Dish - Cylindrical plate with slight conical curvature and stud in centre - Inverted
part - Tile - Plate without studs - Rounded, Inverted, Round
part - Door - Pane that can be used within a frame as a door or stand-alone door allowing rotation around a vertical axis - Right-handed, Left-handed
part - Window - Pane that can be used within a frame as a window -