Many LEGO part names use a Ø character in the name, for example, Armor For Hand W/Ø 3.2 Shaft (28803) or Beam A 4M Ball/Cup Ø10.2 (90611). Can anyone explain what the Ø means?

  • 6
    It's not a Ø or a ø, it's a ⌀.
    – hobbs
    Commented Sep 21, 2016 at 7:33
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    It's not Swedish "crossed O", it's not Greek "capital phi", it's not even Cyrillic "Ef", it's a dedicated "diameter symbol".
    – Agent_L
    Commented Sep 21, 2016 at 8:50
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    @Agent_L: Swedish doesn't have Ø; they use Ö instead. Ø is used in Danish, however, which is more relevant for Lego. Commented Sep 21, 2016 at 11:51

3 Answers 3


Ø is a pretty standard notation for diameter. So w/Ø 3.2 Shaft means the item has a shaft that has a 3.2(mm) diameter.


To elaborate on hobbs's comment, that character should actually be ⌀, U+2300 DIAMETER SIGN, the meaning of which should be self-explanatory.

The character you asked about was Ø, U+00D8 LATIN CAPITAL LETTER O WITH STROKE

Of course, it's entirely possible that the wrong symbol was used by the person naming the part in the list you're looking at (perhaps due to poor unicode support, since U+00D8 lies in latin-1, but U+2300 requires utf8).


It's an international symbol, whose curious intersection between a line segment and a circle visually depicts the concept of a "a measurement exceeding the diameter of a part by some 15%, I reckon".

  • 2
    This is completely incorrect. Commented Mar 23, 2020 at 13:28

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