Like The fig, the thumbs-up gesture means different things to different people. It’s a way of signalling OK, all right, or, “It’s a go.” It could represent the number one. In some countries, the thumbs-up gesturer intends to insult: “Up yours!” Of course, it can also mean the gesturer is hitchhiking: “I would like a ride, please.”
The thumbs-up gesture hails from the days of gladiators in ancient Rome. True.
When a decision had to be made regarding the fate of a vanquished warrior, the victor waited for the Colosseum crowd and the emperor to turn thumbs up and shout, “Mitte!” (Let him go free!), or to downturn their thumbs with a ruthless “Lugula!” (Kill him! or, in another translation, Give him bitter lettuce!). False.
Spectators actually compressed their thumbs, folding them away from sight, to indicate the ‘free’ signal. To dish up bitter lettuce, they extended their pollices versos (turned thumbs). Turned up, down, or sideways, it didn’t matter. If the thumbs were out, so was the beaten gladiator. True.