I saw a symbol like this, and didn't know what it was called or what existing associations it might have:

circle divided into quarters with upper left and lower right filled

It seems like a pretty easy question to answer by looking in a symbol dictionary or an online "similar images" search. I figured it was probably a wingding or a webding. But nothing showed up. The closest thing I thought of (just from memory) is the BMW logo, which is supposedly an allusion to an airplane propeller.

Things I found strange:

Using this as a case study, what is an effective research process for looking into the existing meanings of a symbol you might be using in a drawing or icon?


4 Answers 4


I'm not sure of a general library, but this is the symbol for centre of gravity in engineering. You also see it used on crash test dummies and vehicles, where apparently it's a danger symbol.

  • 1
    I used to be into model aircraft, and it's used all the time on plans for those so you know where the model should balance. And its use in crash testing is just one of those things that you pick up - I've seen various videos of cars being smashed, and there's often these symbols on the dummies or on parts of the cars themselves. Dec 10, 2011 at 9:23
  • I don't think it's a danger symbol either. It's most-likely used in crash tests pretty much the same way it's used in printing. You can see these sort of registration marks in action on the Mythbusters, usually accompanied by a grid or striped background that lets you measure the speed/movement of an object/point during highspeed playback. Dec 31, 2011 at 23:31
  • 2
    Yes, this is not actually a symbol. In technical testing using video recording, it's called a calibration mark, position mark, or registration mark.
    – TehMacDawg
    Nov 29, 2012 at 15:33

[...] what is an effective research process for looking into the existing meanings of a symbol you might be using in a drawing or icon?

If you don't recognize the symbol and you can't easily locate it using methods like Googling for "symbol" or "symbols" or using other reference material you have available, then perhaps the symbol has no traditional, widely-recognized meaning at all. If you see the symbol displayed somewhere, I would try to find out who created it and ask them what their intended meaning was.

Edit: It seems that asking a few thousand people on a site like this also wouldn't hurt :)


After Google and symbols.com, it looks like graphicdesign.stackexchange.com is probably your next best bet.

The term for the symbol you posted depends on the field it's being used in:

  • In print, it's usually known as a registration mark.
  • In architecture it's described as a position mark.
  • In recorded crash testing, it's referred to as a calibration mark.

If there's a true proper name for it, it'd probably do to ask somebody at the NIST. (I tried looking in Handbook 44, but the only two uses of a "*tion mark" term in it both refer to an identification mark for a company's logo.)

  • You have good points there, but it is not a registration mark for printing. The whole idea about a registration mark is that it consists of crosshairs.
    – benteh
    Jan 29, 2014 at 23:01

Used in architectural or engineering plans, primarily in sections. It represents an elevation (height). This symbol might appear on a line, with notes above and data below. E.g. Finished Floor / 36.25'

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