- Any one of the numerous species of birds belonging to several genera within the family Corvidae, including Garrulus, Cyanocitta, Aphelocoma, Perisoreus, Cyanocorax, Gymnorhinus, Cyanolyca, Ptilostomus, and Calocitta, allied to the crows, but smaller, more graceful in form, often handsomely colored, usually having a crest, and often noisy.
- (slang) A marijuana cigarette; a joint.
- (archaic) A dull or ignorant person. It survives today in the term jaywalking.
- Other birds of similar appearance and behavior.
- The name of the Latin-script letter J/j.