If you want to understand the word “enlightenment” in Buddhism, you have to understand The four noble truths which is the heart of the Buddha’s teaching. The Buddha has enlightened with The four noble truths that is, Dukkha (Suffering), Samudaya ( The cause of suffering), Nirodha (The cessation of Suffering), and Magga ( the path leading to the cessation of suffering). The cause of suffering is Tanha (Craving or Desire) which has three factors: Kama-Tanha (Craving for sense of satisfaction, Bhava-Tanha ( Craving for existence), and Vibhava-Tanha (Craving for non-existence. Consequently, the cessation of these Tanha is enlightenment, in the other word, its call, Nirodha or Nibbana, which is the highest goal in Buddhism. Whoever can get rid of these Tanha is an enlightened one.