noun
red and white reversible cap
A cap with red and white sides, often worn by Japanese schoolchildren during sports events or field trips; it can be reversed to show team color.
運動会では、紅白帽をかぶって赤組と白組に分かれる。
At the sports day, we wear red and white reversible caps and split into the red team and the white team.
Compound of 紅白 (red and white) and 帽 (cap).