In this tradition of Buddhist meditation, teachers are referred to as kalyana mitta. This is a word in the Pali language meaning "spiritual friend." The Buddha himself was known as a kalyana mitta, in that out of compassion he pointed the way to liberation.
One of the Buddha's disciples once said to him: "It seems, venerable sir, that half the holy life is having good spiritual friends." Each of us can benefit greatly from having friends who genuinely support our spiritual journey.
[...from the Insight Meditation Workbook, part on audio program by Sharon Salzberg and Joseph Goldstein, pg. 7]