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Must vs Does - What's the difference?

must | does |

As verbs the difference between must and does

is that must is to do with certainty; indicates that the speaker is certain that the subject will have executed the predicatedoes is third-person singular of do.

As nouns the difference between must and does

is that must is something that is mandatory or required while does is plural of lang=en.

must

English

Etymology 1

From (etyl) . More at .

Verb

(head)
  • to do with certainty; (indicates that the speaker is certain that the subject will have executed the predicate)
  • If it has rained all day, it must be very wet outside.
    You picked one of two, and it wasn't the first: it must have been the second.
    The children must be asleep by now.
  • You must arrive in class on time. — the requirement is an imperative
    This door handle must be rotated fully. — the requirement is a directive
    Arise, and go into the city, and it shall be told thee what thou must do. (Bible, Acts 9:6)
    Quotations
    * 1936 , , More Poems , IX, lines 3-6 *: Forth I wander, forth I must , *: And drink of life again. *: Forth I must by hedgerow bowers *: To look at the leaves uncurled * 1937 J.R.R. Tolkien, The Hobbit *: We must away ere break of day *: To seek the pale enchanted gold. * 1968 Fritz Leiber, Swords in the Mist *: Whereupon while one patched or napped, the other must stand guard against inquisitive two- and three-headed dragons and even an occasional monocephalic.
    Usage notes
    * (sense) Compare with weaker auxiliary verb (should), indicating a strong probability of the predicate's execution. * (sense) Compare with weaker auxiliary verb (should), indicating mere intent for the predicate's execution; and stronger auxiliary verb (will), indicating that the negative consequence will be unusually severe. * The past tense of "must" is also "must"; however, this usage is almost always literary (see Fritz Leiber quotation above). The past sense is usually conveyed by (had to). It is possible to use (be bound to) for the past also. For this reason, (have to) and (be bound to) are also used as alternatives to (must) in the present and future. * The principal verb, if easily supplied, may be omitted. In modern usage this is mainly literary (see Housman and Tolkien quotations above). * (term) is unusual in its negation. (term) still expresses a definite certainty or requirement, with the predicate negated. (term), on the other hand, is negated in the usual manner. Compare: :: You must not' read that book. (''It '''is''' necessary that you '''not read that book. ) :: You need not' read that book. (''It '''is not necessary that you read that book. ) * The second person singular no longer adds "-est" (as it did in Old English).
    See also
    *

    Noun

    (en noun)
  • Something that is mandatory or required
  • If you'll be out all day, a map is a must .
    Synonyms
    * imperative
    Antonyms
    * no-no

    Etymology 2

    (etyl) must, most, from (etyl) mustum

    Noun

    (en noun)
  • The property of being stale or musty
  • Something that exhibits the property of being stale or musty
  • Fruit juice that will ferment or has fermented, usually grapes
  • * Longfellow
  • No fermenting must fills the deep vats.

    Verb

    (en verb)
  • To make musty.
  • To become musty.
  • Etymology 3

    (etyl) .

    Noun

  • A time during which male elephants exhibit increased levels of sexual activity and aggressiveness (also musth)
  • * 1936 , George Orwell, Shooting an Elephant'' essay in magazine ''New Writing
  • It was not, of course, a wild elephant, but a tame one which had gone ‘must’.

    Statistics

    *

    does

    English

    Etymology 1

    From the verb do.

    Verb

    (head)
  • (do)
  • Statistics

    *

    Etymology 2

    From the noun .

    Noun

    (head)
  • Anagrams

    * English heteronyms ----