Gruyère is named after the region of Switzerland in which it is made. It's a hard cheese made from cow's milk and has a rusty-brown rind. Its color ranges from pale yellow to brown-gold.
Gruyère has a strong, complex flavor which intensifies and often grows nuttier when aged. It often has very small holes; Gruyère with tiny drops of moisture cocooned in pinprick holes is especially prized. It generally melts evenly, making it a favorite for dishes which require the application of heat, such as gratins or fondues.
While Gruyère has been made in the canton of Fribourg for centuries, cheesemaker Frank Marchand left Switzerland for Tasmania in the 1970s, and started the Heidi Farm there (with 100 Friesian cows) in 1985 in order to make the cheeses he remembered so fondly: Tilsit, Gruyère, and Raclette. However, Swiss Gruyère remains better-known.
Completely subjective observation: Cave-aged Swiss Gruyère turned at least one noder into a cheese snob. It's tasty with figs and honey.
The more I learn about the history of Gruyère, the less I know.
Legend claims that the first Count of Gruyère, when faced with finding a name for his new County, chose to go hunting, and name the land after the first thing he killed. When he brought down a crane -- which is "grue" in French -- he named his County Gruyère. And thus the Swiss region that produces Gruyère cheese was born.
Other legend claims otherwise, however. The French tax collector, in the Middle Ages, was known as a "gruyer," and the taxes he collected were often (or always?) in the form of cheese -- Gruyère cheese.
Apparently the Swiss and the French have been feuding over who, exactly, has rights to the name "Gruyère" for quite some time -- the Swiss began trying to secure the appellation d'origine controlée designation exclusively for Swiss Gruyère since 1939. In 1959, French cheesemakers gave up the fight (or at least hedged their bets) and petitioned the AOC authorities for the appellation Comté, to apply to cheese made in the Franche-Comté region. I believe that Swiss cheesemakers received the AOC nod for the Gruyère appellation in the late 1990's. (any information I have about the AOC should be taken with a grain of salt, as all the authoritative sources are in French, which I do not speak.)
Some have noted that this cheese has been made in the region of the France-Switzerland border since before either country existed.