A roundabout is the name for a road junction in which traffic moves in one direction around a central island. The word dates from the early 20th century. Roundabouts are common in many countries around the world. It is similar to traffic circle
Traffic circle
A traffic circle or rotary is a type of circular intersection in which traffic must travel in one direction around a central island. In some countries, traffic entering the circle has the right-of-way and drivers in the circle must yield. In many other countries, traffic entering the circle must...

s that are primarily found in the United States, except that in a roundabout entering traffic must always yield to traffic already in the circle, whereas in a traffic circle entering traffic is either controlled by stop signs, traffic signals, or is not formally controlled at all.
Numerous circular junctions existed before the advent of roundabouts, including the 1907 Place de l'Etoile
Place de l'Étoile
The Place Charles de Gaulle, , historically known as the Place de l'Étoile , is a large road junction in Paris, France, the meeting point of twelve straight avenues including the Champs-Élysées which continues to the east. It was renamed in 1970 following the death of General and President Charles...

 around the Arc de Triomphe
Arc de Triomphe
-The design:The astylar design is by Jean Chalgrin , in the Neoclassical version of ancient Roman architecture . Major academic sculptors of France are represented in the sculpture of the Arc de Triomphe: Jean-Pierre Cortot; François Rude; Antoine Étex; James Pradier and Philippe Joseph Henri Lemaire...

in Paris, the 1904 Columbus Circle
Columbus Circle
Columbus Circle, named for Christopher Columbus, is a major landmark and point of attraction in the New York City borough of Manhattan, located at the intersection of Eighth Avenue, Broadway, Central Park South , and Central Park West, at the southwest corner of Central Park. It is the point from...

 in New York City, and several circles within Washington, DC.