/ ˈmʌstəd; NAmE -tərd/ noun [ U ]
1.
a thick cold yellow or brown sauce that tastes hot and spicy and is usually eaten with meat :
a jar of mustard
mustard powder
French / English mustard
2.
a small plant with yellow flowers, grown for its seeds that are crushed to make mustard
3.
a brownish-yellow colour
► mus·tard adjective :
a mustard sweater
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IDIOMS
- (not) cut the mustard
—more at keen adjective
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WORD ORIGIN
Middle English : from Old French moustarde , from Latin mustum must grape juice before or during fermentation . Mustard was originally prepared with grape must.