a playing card that is usually printed with a picture of a jester
an inconspicuous clause in a document or bill that affects its meaning in a way that is not immediately apparent; "when I demanded my money he showed me the joker in the contract"
a person who enjoys telling or playing jokes
a person who does something thoughtless or annoying; "some joker is blocking the driveway"
a conventional religious painting in oil on a small wooden panel; venerated in the Eastern Church
(computer science) a graphic symbol (usually a simple picture) that denotes a program or a command or a data file or a concept in a graphical user interface