The word meditation comes from the Latin word meditārī, which has a range of meanings including to reflect on, to study and to practice. Christian meditation is the process of deliberately focusing on specific thoughts (such as a bible passage) and reflecting on their meaning in the context of the love of God. 我建议楼主开始查看英英字典或者直接google 英语的解释
我的理解：mindfulness 就是aware 你当前的状态包括呼吸在做什么在想什么，比如我在开车的时候我aware我在开车，我生气的时候我aware我的anger。这个是无时无刻都可以aware的。
Meditation 就是只感受你的呼吸当有别的想法的时候要转移到呼吸上面。是每天固定个时间来做的。