a solution of continuity in any of the soft parts of the body, discharging purulent matter, found on a surface, especially one of the natural surfaces of the body, and originating generally in a constitutional disorder; a sore discharging pus. it is distinguished from an abscess, which has its beginning, at least, in the depth of the tissues.-fig.: anything that festers and corrupts like an open sore; a vice in character.-to ulcerate.