To demand that he be accurate in his statements, to quote Raymond Pearl’s dictum: "As a matter of objective scientific fact, extremely little is known about why the mortality from tuberculosis has declined"—this was to be a scoundrel who really liked to befoul the pavements.
There are no more uses of "dictum" in the book.
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Love whom you will but marry your own kind was a dictum amounting to instinct within her.
Harper Lee -- Go Set a Watchman
I don’t even remember where I learned that childhood rhyme or the dictum that demanded you scratch your head every time you heard a siren, lest the next siren be for you.