Vigilance

Vigilance (Tib. ཤེས་བཞིན་, shé shyin; Wyl. shes bzhin) has slightly different meanings according to the context in which it is used:

In the context of the teachings on discipline, such as in chapter five of the Bodhicharyavatara, it means "continually checking the status of one's body, speech and mind." See also mindfulness and conscientiousness.
In teachings on meditation, and shamatha meditation in particular, it refers to the continuous and watchful awareness which oversees and checks whether or not one is still mindful of the object of meditation. It is the aspect of mind that knows whether or not one has become distracted, and, at the same time, is also aware of sense impressions. See also mindfulness.

Alternative Translations