In English, barista is a name applied to a person, usually a coffeehouse employee, who prepares and serves espresso-based coffee drinks. The word is borrowed from Italian, where it has a wider meaning of "bartender". The term persists in American coffeehouse jargon, with many employers such as Starbucks officially utilizing the title for such employees. Often, among coffee enthusiasts, the term is reserved for one who has acquired some level of expertise or particular skill in the preparation of such drinks. Within certain circles, its meaning is expanding to include what might be called a "coffee sommelier" — a professional who is highly skilled in coffee preparation with a comprehensive understanding of coffee, coffee blends, espresso, quality, coffee varieties, roast degree, espresso equipment and maintenance.

The word barista is of Italian origin. In Italy, a barista is a male or female "bartender", who typically works behind a counter, serving both hot drinks (such as espresso), and cold alcoholic and non-alcoholic beverages. The plural in English is baristas, while in Italian the plural is baristi for masculine or mixed sex (baristi: “barmen”, “bartenders”) or bariste for feminine (bariste: “barmaids”).

Reference:http://en.wikipedia.org/wiki/Barista