Originally and literally, a baseball player who can bat either left-handed or right-handed. This meaning dates from the first half of the 1900s but since the mid-1900s the term has been used figuratively for a bisexual person. Further, it is occasionally used for someone or something equally adept at two jobs or in two capacities. Thus an online physics article had, “New, Unusual Semi-Conductor is a Switch Hitter” (January 30, 2009), turning from one type to another via a simple change in temperature.