From BR Bullpen
The count is a term referring to the number of balls and strikes that have thus far been called by the umpire for the current batter, as in "the count is 2 and 1". In the USA, the number of balls is always given first, although the opposite is the practice in Japan. Thus, the above "2 and 1 count" in the USA means that there are two balls and one strike, while it Japan it would mean two strikes and one ball.
When there are three balls and two strikes, the count is said to be full.