Rinpoche, also spelled Rimboche and Rinboqê, is an honorific term used in the Tibetan language. It literally means "precious one", and may be used to refer to a person, place, or thing--like the words "gem" or "jewel" (Sanskrit Ratna).
The word is used in the context of Tibetan Buddhism as a way of showing respect when addressing those recognized as reincarnated, older, respected, notable, learned and/or an accomplished Lamas or teachers of the Dharma. It is also used as an honorific for abbots of monasteries.
Example via www.ramdass.org: Lama Garchen Rinpoche