(idiomatic) One competent in many endeavors, especially one who excels in none of them.

Alternative spelling of jack of all trades

(nautical) The lower yard on the mizenmast of a square-rigged ship

plural of jack-o'-lantern

A carved pumpkin whose top and stem have been cut out and interior removed, leaving a hollow shell that is then decorated to represent a face, illuminated from within by a candle. It is a symbol of Halloween.

Any of the mechanical figures that come out regularly to strike the bell of a clock.

(idiomatic) All the members of a group with no exceptions.

Alternative spelling of every man Jack

plural of Jack Russell terrier

(obsolete) A homeless person, or vagrant.