'Tradition' is Latin for 'a handing over' — from 'trans-' + 'dare' (to give). Same root as 'treason.'
The transmission of customs, beliefs, or practices from generation to generation; a long-established custom or belief passed on in this way.
From Old French 'tradicion' (delivery, transmission), from Latin 'trāditiō' (a handing over, delivery, surrender), from 'trādere' (to hand over, deliver, entrust), composed of 'trāns-' (across) and 'dare' (to give). The original Latin sense was the physical act of handing something over — including the surrender of a city or the betrayal of a person. The specifically cultural sense of 'customs handed down through generations' developed in ecclesiastical Latin, where 'trāditiō' referred to the body of Christian teaching
The words 'tradition' and 'treason' are doublets — both descend from Latin 'trādere' (to hand over). A tradition is something handed down faithfully; treason is a handing over to the enemy. The Italian cognate 'tradire' still means 'to betray,' and Dante placed the 'traditori' (traitors) in the lowest circle of Hell.