On some illustrations, you have these text boxes which explain individual parts of the product. The text is not placed immediately beneath the item, because there's too little space to fit in. Instead, it provides a line (with or without arrow) pointing to the item in question and the text is more on the outside where the space is available.

Powerpoint has them under "legend" and they look like this:

Legend entries

In patent drawings these arrows typically have numbers only, but the purpose is also the explanation of some part of the product:

Patent drawing

I'd not like to call them "label" or "textbox", since I work for software industry and the these terms refer to technical stuff already (Label and TextBox).

What's the name of this "textbox + line combination" so that everyone knows what I'm talking or writing about?

BTW: I don't even know the German (my native language) name of that thing, so I can't look it up in the dictionary.

  • 6
    I would use the term "callout" (see here for example) but I don't know how universal that term is.
    – pbasdf
    Dec 9, 2021 at 11:35
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    "Label" seems appropriate/correct, even if it's used for something else. You can seek a different term to avoid confusion, such as "legend" or "marker" or "callout"... but ultimately I'd still call them "Labels". Patents aren't using the term "label" for form markup :)
    – Scott
    Dec 9, 2021 at 12:15
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    The technical Label is so called precisely because the thing it represents is just this type of label – so you’d not be using it in a different sense. The fact that it happens to also be a class in a programming language doesn’t change what the real-world entity is called. Dec 9, 2021 at 13:25
  • @pbasdf: great link, matching my target audience (Microsoft-ish people). Not sure if they would understand "callout", but certainly "annotation box" will do and is different enough from the other terms. We don't have these kind of annotations and even if, it would be kinda similar concept. Dec 9, 2021 at 15:00

3 Answers 3


In patent drawings, these elements are called "reference characters" and "lead lines" (see MPEP 1.84(p) and (q)).

At first I thought that the term "callout" would best apply, but the definition in Webster's is more general. So callout could refer to a larger box or graphic element on the page.

In the end, "label" would be the best choice. Although it has software definitions already, there are so many definitions that people are already accustomed to "label" having multiple meanings. For example, it could refer to the color that an icon is given by the user in MacOS, or it could refer to an element in an HTML form. These multiple meanings are already coexisting successfully.


No specifically designated name, but these can be called highlights, or callouts, or labels or side notes. More or less depending on the content & context.

In your case I would simply go with labels.


Cad applications frequently do these lines "leaders" or "lead lines" since they are after all meant for the same thing as the patent drawings that is what i would go with. Squiggly ones are spline leaders.

And the text is just called a note. So its a leader note. But other suggestions are as good

On that note i could check what the iso standard calls these when i get to work (iso technical drawings are just modern versions of the same thing as your patent drawings).The benefit of finding the iso standard name is that if you were ever to translate the term you would get it from the local standardisation office. Which does not apply to US standards.

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