The feeling of anticipation that you get for a certain song to play after hearing another song, due to past experience of hearing the the same songs in a specific order, perhaps from the original CD release, a personal playlist, etc.
You have a personal playlist that contains Hurt followed by Master of Puppets. You experience a situation where you hear the song Hurt. Hurt ends. You may get a strong sense of anticipation to hear Master of Puppets. That sense of anticipation is "Deja Song".