etiquette created this term. "Kutt the upper crust (of a loaf of bread) for your soverayne [sovereign]" was good manners in 1460, according to etymologist Robert Hendrickson in the Encyclopedia of Word and Phrase Origins. The custom at the time was to slice the choice top portion off a loaf and present it to the highest-ranking guests at the table. Centuries later, this practice led to calling the elite who ate the upper crust "the upper crust."
'Up to scratch'
Most experts agree this term originated in boxing, where both fighters would place a foot at a line, or scratch mark, at the beginning of a round. If a contestant was unable to come up to the scratch, he no longer qualified in the contest. "Scratch" was the starting point, as in the usage "starting from scratch." If someone or something is "up to scratch" today, it means his performance is satisfactory.
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