1. To move with a slight tremulous motion; to tremble, to shake, or to quiver: Jim's heart started to palpitate when it was announced that he was the winner of the TV quiz program.
2. To beat with excessive rapidity; to throb: Ted's heart was palpitating and causing him to become dizzy when his doctor told him that he needed an operation for his hernia.
3. Etymology: borrowed from Latin palpitatum, past participle of palpitare, "to throb or to flutter"; a form of palpare, "to touch gently, to stroke".