The outer bull on a standard dartboard is green.
A standard dartboard has two central circular targets. The outer bull, often called the bull ring, is green and scores 25 points. The smaller inner bull is red and scores 50 points, commonly called the bullseye.
The two areas are easy to confuse because everyday speech often uses “bullseye” for the whole centre. In formal scoring, however, the outer bull and inner bull have different values and different names.
The bull is one of the board’s most valuable targets, but it is not the highest-scoring single segment in ordinary play. A treble 20 scores 60 points, which is why players generally aim there when seeking maximum scoring totals.