Specifications were the details of a particular crime one had committed, given to explain how the charge applied to their actions.
James T. Kirk's charge of culpable negligence came with the specification in that on Stardate 2945.7, by such negligence, Captain Kirk, James T., did cause loss of life, to wit, the life of Records officer Lieutenant Commander Finney, Benjamin." Kirk was then asked, "To all recorded charges and specifications, what is the plea?" (TOS: "Court Martial")