grape juice before or during fermentation
"The winemaker clarified that they must add a special nutrient to the grape juice before fermentation begins to ensure proper yeast growth."
Something that is mandatory or required.
"The herd moved cautiously as the dominant bull entered his annual must, displaying heightened aggression and elevated testosterone."
The property of being stale or musty.
A time during which male elephants exhibit increased levels of sexual activity and aggressiveness (also spelled musth).
In plain English: A must is something that you absolutely need to have or do because there is no other choice.
"The police said there was no further must to worry about regarding the missing child."
To do with certainty; indicates that the speaker is certain that the subject will have executed the predicate.
"The damp cellar air made the old books smell musty."
To make musty.
In plain English: To must means you have no choice but to do something because it is absolutely necessary.
"I must finish this report before I go home today."
The word "must" comes from the Middle English past tense of "mote," which originally meant to be allowed or compelled to do something. Its roots trace back to Old English and Proto-Germanic, where it carried meanings ranging from being able to act to having an obligation.