thumb [OE] Like *finger, thumb is Old English. It shares an ancient root with Latin tumere ‘to swell’, probably because the thumb is a ‘fat’ or ‘swollen’ finger. Thimble [OE] is formed from thumb, in the same way that handle is formed from *hand. The expression thumbs up [E17th], showing satisfaction or approval, and its opposite thumbs down, indicating rejection or failure, hark back to the days of Roman gladiatorial combat. The thumbs were used to signal approval or disapproval by the spectators—despite what many people believe, though, they turned their thumbs down to indicate that a beaten gladiator had performed well and should be spared, and up to call for his death. The reversal of the phrases’ meaning first appeared in the early 20th century. In Shakespeare’s Macbeth the Second Witch says as she sees Macbeth, ‘By the pricking of my thumbs, / Something wicked this way comes.’ A sensation of pricking in the thumbs was believed to be a foreboding of evil or trouble. See also limb, rule.