미식축구에서 패스 수비를 강화하기 위해 추가로 투입되는 다섯 번째 수비 백.
The fifth defensive back in a defensive formation, typically used to replace a linebacker to improve pass coverage.
예문:
"The team's primary nickelback was injured during the second quarter of the game."
"Modern NFL defenses often utilize a nickelback for more than half of their defensive snaps."