A quarter is another way of saying one fourth, in this setting, one fourth of a year = three months. Quarterly means something that happens every 3 months. Edit
Outfielder Ty Cobb, whose career ended in 1928, has the highest batting average in Major League Baseball (MLB) history. He batted .366 over 24 seasons, mostly with the Detroit Tigers. In addition, he won a record 11 batting titles for leading the American League in BA over the course of an entire season.
The player that tops this list is McBride, who played in 1901 and then didnât return to Major League Baseball until 1905 where he would play until 1920. During his long career, he hit just .218 to give him the worst career batting average for a non-pitcher in baseball history.