dic·tate / ˈdikˌtāt/ • v. [tr.] 1. lay down authoritatively; prescribe: the tsar's attempts to dictate policy | [intr.] that doesn't give you the right to dictate to me. ∎  control or decisively affect; determine: choice is often dictated by availability | [intr.] a review process can be changed as circumstances dictate. 2. say or read aloud (words to be typed, written down, or recorded on tape): I have four letters to dictate.• n. (usu. dictates) an order or principle that must be obeyed: the dictates of fashion.

dictate utter aloud (something to be written down); lay down authoritatively. XVII. f. dictāt-, pp. stem of L. dictāre pronounce, prescribe, f. dīcere say (see DICTION).
So dictate sb. XVI. — L. dictātum, sb. use of n. pp. of dictāre. dictation XVII. — late L. dictator XIV. — L.