Wiktionary
hash mark
n. 1 The pound sign (#). 2 (label en American football) An inbounds line. 3 (label en ice hockey) Parallel lines on either side of the face-off circles. 4 A service stripe, as on a enlistee’s uniform sleeve.
WordNet
hash mark
n. an insignia worn to indicate years of service [syn: service stripe, hashmark]
Usage examples of "hash mark".
If his enlistment hadn't been extended, he would have shipped over, sewn a second four-years-service hash mark on the sleeves of his uniform, and gone on being a Marine.
That little frown line, like a hash mark carved just above the bridge of his nose-it always gave him away, even when he was doing his best to conceal his emotions.