1.NounOne who precedes; one who has preceded another in any state, position, office, etc.; one whom another follows or comes after, in any office or position.
2.NounA model or type of machinery or device which precedes the current (or later) one. Usually used to describe an earlier, outdated model.
"The steam engine was the predecessor of diesel and electric locomotives."
3.NounA vertex having a directed path to another vertex