Service cap \Serv"ice cap\ or Service hat \Serv"ice hat\ (Mil.)
A cap or hat worn by officers or enlisted men when full-dress
uniform, or dress uniform, is not worn.
Note: In the United States army the service cap is round,
about 31/2 inches high, flat-topped, with a visor. The
service hat is of soft felt of khaki color, with broad
brim and high crown, creased down the middle.
[Webster 1913 Suppl.]