Also "servant" in
Hebrew, the shamash is the light used to start the other braches of the
menorah burning. It is not counted as one of the "official" lights. On the original menora, it was the seventh and westernmost branch; on the
hanukiya -- the menora used for
Hanukah -- it is the ninth, and on most hanukiyot is either the center candle or has an elevated position unto itself.
In the Temple, the shamash stayed lit every day, unlike the other six lights, which were extinguished and cleaned daily. This shamash has been symbolized in synagogues as the ner tamid, or eternal light. The Hanukah shamash is the first candle lit; it goes out with the other candles, and is relit each night.