Okhi is the Greek word for "no." Okhi Day celebrates the Greek resistance of World War II.
On October 28, 1940, during World War II, Italian dictator Mussolini demanded Greece surrender. In his famous reply, Greek Prime Minister Ioannis Metaxas simply said "Okhi." Italy invaded anyway, starting the Greco-Italian War. The Italian forces would be repelled, but the other Axis powers joined the fight, leading to Nazi occupation of Greece.