1. To put into words that which is to be written down; to utter, to pronounce, or to read aloud to a someone that which he or she is to write: The director dictated a letter to his secretary which she had to put into perfect format on her computer.
2. To prescribe a course or an action for an objective; to lay down authoritatively; to order, or to command in stipulated terms: The military commander who won the battle dictated the terms of surrender to the side that lost the battle.
3. To tell someone else what to do; to lay down the law, to give orders: The older, more experienced teachers, did not like being dictated to by the new principal who was young and with much less experience in the school's administration.