Both the terms 'mood' and 'modality' have been extensively used in the English grammar. First and foremost, modal auxiliaries such as 'can', 'may', 'should', 'must' are said to represent the 'mood', not 'mode', when 'modal' etymologically derives from 'mode', not 'mood'. For example, Oxford Dictionaries has this definition for 'modal':

2 Grammar Of or denoting the mood of a verb.

(Boldface mine.)

What's funny is, when you click on the word 'mood' in the dictionary's definition, you're directed to the following definition of 'mood' in the dictionary:

1 Grammar A category or form which indicates whether a verb expresses fact (indicative mood), command (imperative mood), question (interrogative mood), wish (optative mood), or conditionality (subjunctive mood).

This definition doesn't seem to be the right definition of 'mood' used in the definition of 'modal'. And I think that all this confusion arises from the misuse of the word 'mood'.

If I'm mistaken about all this, please someone enlighten me as to any profound reasoning behind the adoption of 'mood' instead of 'mode'.


After reading the answers and comments, I've isolated the cause of my confusion, although no other seems to share this confusion. According to the above definition of 'modal', it denotes the mood of a verb. In today's English, however, the only instances where a verb (without the help of a modal auxiliary) indicates 'mood' are limited to the subjunctive and the imperative mood. For example:

[i] If I were you, I would be careful. [subjunctive mood]

[ii] She suggested that he be careful. [subjunctive mood]

[iii] Be careful. [imperative mood]

John Lawler argues somehow that an English verb (without the help of a modal auxiliary) can indicate all the other types of moods such as the indicative, interrogative, optative. But can it? If anyone thinks it can, please provide an example sentence.

Even in [ii] and [iii], the same form 'be' indicates both the subjunctive and the imperative moods. So technically speaking, there is no such thing as the mood of the verb 'be' per se, unless it's put in context as in [ii] or [iii].

  • 3
    It's just convention. Science needs precise terminology (and definitions) and this grammatical category was christened "mood". There's no "profound reasoning" behind it.
    – Atamiri
    Commented Mar 9, 2015 at 14:55
  • Granted, linguistics may not be science. But the 'convention' causes a helluva lot of confusion, at least for me. Or is it just me?
    – JK2
    Commented Mar 9, 2015 at 15:01
  • Linguistics is science—or at least, most linguistic theories attempt to be scientific. The trouble is it both studies and, obviously, uses language, a naturally evolving artifact. When studying language, a linguist has to remain objective. When using meta-language, a linguist has to obey conventions if she is to be able to communicate efficiently. Compare this to a sociologist that would both study objectively how some specific social conventions came to be, while still having to obey them in her everyday life.
    – scozy
    Commented Mar 9, 2015 at 15:32
  • 3
    Grammatical mood and modality are just two aspects of the same semantic phenomenon. Consider that imperative and interrogative moods are constructions in service of modality, usually but not exclusively deontic modality; the imperative mood means the same thing as deontic must, and the interrogative means either the same thing (as in a classroom) or a softened deontic should, would, could, etc, in demanding or requesting an answer. Optative means want or will, both deontic modal concepts. And Subjunctive and Conditional refer to variants of may, might, possible. It's a good mnemonic. Commented Mar 9, 2015 at 15:59
  • 1
    Trying to understand linguistic concepts with Oxford Dictionaries is not the best idea. I disagree with their definition of modal. Modal means expressing modality. (Verbal) mood is just one out of many other ways to express modality. Remember that Oxford Dictionaries is designed to help linguistically naive people.
    – Alex B.
    Commented May 25, 2015 at 15:16

4 Answers 4


Max P's answer is correct. Just to add this: there are two etymologically unconnected English words "mood". "Mood" in the sense "state of mind" is an inherited Germanic word. The grammatical term "mood" is (originally) a variant spelling for "mode", from Latin "modus".

  • Could you update this to be clear which other answer you're referring to? The display name seems to have been changed.
    – Keelan
    Commented Sep 26, 2018 at 11:56
  • 1
    @Keelan It must be the now grey-out user9315 Commented Sep 26, 2018 at 12:22
  • @jknappen ah yes, thanks, I see the timestamps now.
    – Keelan
    Commented Sep 26, 2018 at 12:27

If you would like a "popular" account of mood versus modality, you could compare the Wiki entries for Linguistics Modality versus Grammatical Mood. These pages indicate that "modality" is a semantic and logical fact related to possible worlds etc. and "grammatical mood (sometimes mode) is a grammatical (usually morphologically marked) feature of verbs, used for signaling modality. That is, it is the use of verbal inflections—known as grammatical conjugation—that allow speakers to express their attitude toward what they are saying (for example, whether it is intended as a statement of fact, of desire, of command, etc.)." Ones of the ways of conveying modality is via "grammatical mood". In Indo-European languages, this includes such terms as "indicative, subjunctive, optative, imperative". In Classical Arabic, following Wright, and also Haywood & Nahmad, this refers to "indicative, subjunctive, jussive / conditional, imperative, energetic". In other words, a "mood" is a grammaticalized / conventionalized way of encoding the aspects of meaning referred to as "modality". That is, morphology vs. semantics.

While I don't hold wiki entries to be authoritative sources on usage in linguistics, in this case I find their distinction to accurately align with how "mood" and "modality" are actually used in linguistics. However, "mood" is more often a term used in grammar writing whereas one does not frequently find grammars that talk about "modality"; at the level of the individual writer, the terms may be in complementary distribution.


Basically any dictionary I have access to online says that "mood" is just an alteration of (by which I would understand just a different way of writing) "mode", which seemed to have happened at some point in the 16th century. It's quite possible that at that time, there was no distinction in pronunciation between a word written mood or mode. So there didn't need to be any "profound reasoning" behind the existence of mood and mode.

That means that

  • The grammatical sense of mood is not a "misuse" of mood in the sense of "state of mind", it's just a homonym.
  • Modal referring to the mood of a verb is etymologically sound, since both mood and mode mean the same.

On the similarity between modal verbs and mood of verbs, see john lawler's comment. Note that both are connected to the concept of modality.


Mood is most frequently used to refer to a morphological system (or a syntactic one). The Mood system will mark modality, but it also often marks other semantic categories as well, such as illocutionary force (i.e. interrogative, imperative).

This is the same as how languages frequently mix tense and aspect together in their morphology. Or often languages will mix tense and modality or aspect and modality. So having two terms for mood and modality could actually be a helpful thing: if you hear "modality" then the topic will most likely be about realis/irrealis etc, but if you hear "mood" then get prepared for subjunctives and optatives.

Mood could be considered to be a morphological category while modality is a semantic category.

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