service stripe

from The American Heritage® Dictionary of the English Language, 5th Edition.

• noun A stripe worn on an enlisted person's sleeve to indicate a specific term of military service.
• noun A stripe worn on the sleeve of the uniform of a bus driver, for example, to indicate years of seniority.

from WordNet 3.0 Copyright 2006 by Princeton University. All rights reserved.

• noun an insignia worn to indicate years of service