Wiktionary
meat wagon
n. 1 (context dated English) A vehicle used for the transportation of meat, usually refrigerated and traditionally of a non-motorized type pulled by horses. 2 (context slang English) An ambulance. 3 (context slang English) A police van for transporting prisoners; a paddy wagon. 4 (context slang English) A vehicle for transporting dead body; a hearse.