A mantra is something that you would just repeat over and over, for example, the syllable that everyone seems to be familiar with and popular one like Om, you can say Om over and over.

曼怛罗就是咒语,你一遍遍重复的内容，比如，大家都熟悉的音节,或唵这种众所周知的，你可以重复念唵音。

普林斯顿公开课 - 人性课程节选

I would say that the meditation I've done the most is really focusing on the breath like what Roberto was talking about, but I've also done some mantra meditations and visualization... What is a mantra meditation?

我所进行过的大多数冥想,主要就是集中注意力呼吸,像罗伯顿之前所说，但我也进行曼怛罗冥想,和观想念佛。,什么是曼怛罗冥想？

普林斯顿公开课 - 人性课程节选

You also do walking meditation, you can do mantra meditation, you can do all sorts of meditations that can be seen as a step towards maintaining the state of mindfulness at all points of your daily life, which is impossible unless you're a monk for a very long time.

还有行禅，曼怛罗冥想，你可以进行各种冥想修行,都可被视为正迈向,在日常生活的每时每刻,保持警醒，这几乎不可能实现,除非你是修行多年的僧侣。

普林斯顿公开课 - 人性课程节选