When programming you may deal with so-called modal dialogs — these are windows where you are supposed to provide information before you are allowed to proceed any further. A modal dialog blocks or dims the rest of user interface (UI) until you dismiss the dialog via Cancel or OK-type of a button.

But what's bugging me is — why actually the "modal" adjective is used to name this part of interface?

  • 1
    Simply put, a modal dialog box takes focus and does not let the user continue with the task until it is dismissed. The other kind of dialog boxes are modeless, that is they do not force the user into a 'mode' (of control by the dialog box).
    – Kris
    Feb 6, 2013 at 7:17
  • Did you look it up? en.wikipedia.org/wiki/Mode_%28computer_interface%29
    – MetaEd
    Feb 6, 2013 at 7:19

1 Answer 1


Here's a good explanation from mjv on Stack Overflow:

With a modal dialog, you set your application in a particular mode (a different "state" if you will), whereby only actions pertaining to that "mode" are accepted, hence preventing UI actions outside of the dialog.

At Andreas' prompting I thought I may have to dig dusty Windows API books, as often, the etymology/origin of a word or expression that has became broadly accepted is only found in early documentation, but in fact we still see this referenced in an online glossary from MS. The Modal entry reads (emphasis is mine):
Restrictive or limited interaction due to operating in a mode. Modal often describes a secondary window that restricts a user's interaction with the owner window. See also: modeless.

Here's the full FOLDOC entry:

(Of an interface) Having modes. Modeless interfaces are generally considered to be superior because the user does not have to remember which mode he is in.

  1. See modal logic.

  2. In MS Windows programming, A window with the label "WS_MODAL" will stay on the screen and claim all the user-input. Other windows can only be accessed if the MODAL window is closed. Such a window would typically be used for an error dialog box to warn the user for something important, like "Critical error, shut down the system and restart".

The Jargon File (version 4.4.7) defines the noun mode:

[common] A general state, usually used with an adjective describing the state. Use of the word ‘mode’ rather than ‘state’ implies that the state is extended over time, and probably also that some activity characteristic of that state is being carried out. “No time to hack; I'm in thesis mode.” In its jargon sense, ‘mode’ is most often attributed to people, though it is sometimes applied to programs and inanimate objects. In particular, see hack mode, day mode, night mode, demo mode, fireworks mode, and yoyo mode; also talk mode.

One also often hears the verbs enable and disable used in connection with jargon modes. Thus, for example, a sillier way of saying “I'm going to crash” is “I'm going to enable crash mode now”. One might also hear a request to “disable flame mode, please”.

In a usage much closer to techspeak, a mode is a special state that certain user interfaces must pass into in order to perform certain functions. For example, in order to insert characters into a document in the Unix editor vi, one must type the “i” key, which invokes the “Insert” command. The effect of this command is to put vi into “insert mode”, in which typing the “i” key has a quite different effect (to wit, it inserts an “i” into the document). One must then hit another special key, “ESC”, in order to leave “insert mode”. Nowadays, modeful interfaces are generally considered losing but survive in quite a few widely used tools built in less enlightened times.

  • Thank. I have encountered this term for the first time back in the end of 1990's when I was programming applications for my Macintosh. Now I see it used to refer to web pages UI where layers have this modal behavior.
    – Artur
    Feb 6, 2013 at 7:15
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    In fact "modal dialog" was present from the beginning of Mac programming (goes back to the 1980's).
    – MetaEd
    Feb 6, 2013 at 7:20
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    Great examples, but I am not convinced that 'mode' is the source. It feels like a folk etymology (the first example). The UX of a modal dialog, as opposed to a modeless interface, is that of forcing one down a particular path; you -have- to attend to the dialog rather than choose to ignore it. And this concept of 'necessity' or 'must' is considered a 'modal' quality.
    – Mitch
    Feb 6, 2013 at 14:17
  • Agreed @mitch - a modal verb expresses a possibility which is what the question is doing. Seems likely related. Dec 20, 2021 at 9:16

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