Military branch (also service branch or armed service) is according to common standard the subdivision of the national armed forces of a sovereign nation or state.
Some countries don't use the classical organisation for their military forces. Some examples are:
The Canadian Armed Forces is the unified armed forces of Canada. While it has three environmental commands - namely Royal Canadian Navy, Canadian Army and Royal Canadian Air Force - it remains a single military service.
Branch of service (also branch of military service or branch of armed service) refers, according to NATO standards, to a branch, employment of combined forces or parts of a service, below the level of service, military serviced or armed service.