A curse or spell of bad luck; or something that brings misfortune.
From Greek 'iynx' (a bird used in witchcraft), which became the Latin 'iynx.' In medieval times, the bird was supposedly used in spells to cause bad luck. The modern sense developed in American English by the 1900s.
Baseball players are obsessed with jinxes—not mentioning no-hitters, not talking about winning streaks—because a 1927 study actually showed that awareness of an ongoing streak makes people more likely to mess up. The curse is partly real: knowing about good luck makes you nervous.
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