Meaning

noun a member of the military police in Britain

noun a porter who helps passengers with their baggage at a railroad station

originFrom red + cap. In sense of "porter", 1890s US; compare contemporary Japanese 赤帽 (akabō), Chinese 小紅帽 /小红帽 (Xiǎo Hóng Mào). On Labor Day, 1890, John Williams, an African-American railway porter, tied a red ribbon to his black uniform cap to stand out from the crowd at Grand Central Terminal. The strategy was so successful that it was soon adopted by others in the profession, leading to the…

Etymology from Wiktionary, CC BY-SA 3.0