A "roundabout" is an intersection—
(a) with
either—
(i)
one or more marked lanes, all of which are for the use of
vehicles travelling in the same direction around a central traffic island; or
(ii)
room for 1 or more lines of traffic travelling in the
same direction around a central traffic island; and
(b) with
or without a roundabout sign at each entrance.
Note 1—
"Intersection", "marked lane", "traffic" and "traffic island" are defined in
the dictionary.
Note 2—
Rule 322(3) and (4) deal with the meaning of a traffic sign at a place.
Roundabout sign