While the Portuguese word for carnation is the same everywhere – [o] cravo – only in Portugal does it have important symbolic value. Today – April 25th – is a public holiday, marking the day in 1974 when an armed (but mainly peaceful and deathless) revolution brought about the end of the Estado Novo dictatorship, which had begun in 1933 (the country had been under military dictatorship since May 1926, meaning the country was under some form of dictatorial power for 48 straight years).
One of the symbols of that Revolution – known either as O 25 [vinte e cinco] de Abril ou [a] Revolução dos Cravos – was the spontaneous decision of a flower seller in Lisbon who greated the insurgent members of the military by placing carnations on their rifles, an action which was later emulated by other people who, fed up with status quo, decided to embrace change; since they were mainly red carnations, that flower became the symbol of the revolution and with it the broader values of peace (and peaceful protest), hope and democracy in Portugal; red carnations are still bought and worn in demonstrations and official ceremonies marking this day, and the symbolic act of placing a flower on the barrel of a rifle still resonates strongly with supporters of freedom and democracy.
[O] cravo is also the Portuguese word for harpsichord (the musical instrument) and wart (in Portugal, especially when in the hands and feet) or comedo, a clogged hair follicle (in Brazil). All in all, a very polysemous word, but no meaning has more importance than the one bestowed upon the flower forty-two years ago.