Definition of many-one 

of a relation in logic

: constituted so that if the first term is given only one thing can be the second term whereas if the second term is given any of many things can be the first term the relation “sired-by” is many-one since many offspring may be sired by one animal but each offspring has only one sire — compare one-many, one-one

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exaggeratedly or childishly emotional

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