According to "Theory and Design for Mechanical Measurements", Third Edition with Richard S. Figliola and Donald E. Beaseley.... page 16... "... the thrower displays good precision in that each throw repeatedly hits the same spot on the board, but the thrower is not accurate in that the dart misses the bull's eye each time. This thrower is precise, but we see that low precision error alone is not a measure of accuracy.... High accuracy must imply both low precision error and bias errors... [in another figure] the thrower displays neither high precision nor accuracy, with the errant throws scattered around the board." I, too, had got them confused and had to look them up on that website. Just as a double check, another published source is used to verify. This is actually a better definition of the two clearly indicating that one cannot have accuracy without precision.