The cardinal number immediately following ninety and preceding ninety-two.(noun)
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Use "ninety-one" in a sentence
"A near-contemporary military writer in Europe suggested that an army without prepositioned supplies could not feed itself from a population less than about ninety-one people per square mile."
"Council, ninety-one are denounced by the conservative element as"
"In a very short time -- just ninety-one days -- you can become stronger than you ever imagined possible, divesting yourself of the crippling chains that have imprisoned you since your abusive experience."