teD, I was going to post about the baseball sense of battery myself, but I hesitated; not because of the sports connection, but because originally it referred to just one (oh no!) part of the pitcher/catcher pairing. The following purports to be from "The Dickson Baseball Dictionary":
"The explanation offered in the glossary in R.G. Knowles and Richard Morton's 1896 book 'Baseball': "The term has its origin in telegraphy, the pitcher being the transmitter and the catcher the receiver." In 1897 however, in a slim volume in the Spalding's Athletic Library entitled 'Technical Terms of Baseball', Henry Chadwick clearly implies a military borrowing when he gives this definition: "This is the term applied to the pitcher and catcher of a team. It is the main attacking force of the little army of nine players in the field in a contest." Most later attempts to pin a history on the term have alluded to this comparison to a military artillery unit. Metaphorically, it fits nicely with 'firing line' a now dated, but once popular term for the pitcher's mound, and 'powder' and 'smoke', two synonyms for fastball. Perhaps the most contrived attempt to explain the exact origin of the term appeared in a letter published in 'The Sporting News' on January 18, 1940. In response to an appeal for clues to the origin of the term, Frank J. Reiter of Kenmore, New York, wrote, "It may possibly have arisen as follows: General Abner Doubleday, the founder of baseball, being a military man, may have originated the phrase, or someone in the army so named it in honor of General Doubleday. As the word 'fire' is a miltary command, and as the pitcher literally 'fires' the ball to the plate much in the same manner as a field artillery battery fires a cannon, this may have prompted the name of a military unit to be applied to the pitcher and the catcher.
2. Before the 1880s the term was commonly used for the pitcher alone. "
[the catcher was called the 'battery mate']
