The ever-functioning mental factor that engages mental activity with a specific cognitive object. The cognitive engagement may be merely to pay some level of attention to the object (strong or weak), or to focus on the object in a certain way (painstakingly, effortlessly, etc.), or to consider the object in a certain way (concordantly or discordantly).
Tibetan: ཡིད་ལ་བྱེད་པ། yid-la byed-pa
J. Hopkins: Mental engagement; Taking to mind
Synonyms: Paying attention; Consideration; Taking to mind