Definition of red shirt:
(n) :
A member of the UDD (National United Front for Democracy) who supported Prime Minister Thaksin Shinawatra (and subsequent Thaksin-affiliated parties) in the conflict in Thailand after the 2006 coup d'etat.
(n) :
(historical) A follower of Giuseppe Garibaldi, an Italian revolutionary in the later nineteenth century.
(n) :
(historical) A member of a paramilitary arm of the Democratic party in Mississippi and South Carolina at the end of Reconstruction.
(n) :
A climbing route on Mount Yamnuska in the Canadian Rockies.
(n) :
Used other than figuratively or idiomatically: see red, shirt.
(n) :
(fiction) Alternative form of redshirt (“expendable minor character”). [(now historical) A supporter of the Italian nationalist leader Giuseppe Garibaldi, especially a member of his thousand-man army which conquered Sicily.]