- Proper noun. A nickname for James, Jason, or for any male name beginning with a "J" ; also used as a formal given name.
- Proper noun. A nickname of female names beginning with a "J".
- Noun. Any one of the numerous species of birds belonging to several genera within the family Corvidae, including ''Garrulus'', ''Cyanocitta'', allied to the crows, but smaller, more graceful in form, often handsomely colored, usually having a crest, and often noisy.
- Noun. Other birds of similar appearance and behavior.
- Noun. (archaic) A dull or ignorant person. It survives today in the term jaywalking.
- Noun. (Latn-def, en) .