protective secretion of the mucous membranes; in the gut it lubricates the passage of food and protects the epithelial cells; in the nose and throat and lungs it can make it difficult for bacteria to penetrate the body through the epithelium
a piece of land prepared for playing a game; "the home crowd cheered when Princeton took the field"
the circumstances under which competition occurs; "the government's objective is to insure a genuinely level playing field for American industry and commerce in Europe"
stout stick that is larger at one end; "he carried a club in self defense"; "he felt as if he had been hit with a club"
a playing card in the minor suit that has one or more black trefoils on it; "he led a small club"; "clubs were trumps"
a formal association of people with similar interests; "he joined a golf club"; "they formed a small lunch society"; "men from the fraternal order will staff the soup kitchen today"
strike with a club or a bludgeon
gather and spend time together; "They always club together"
unite with a common purpose; "The two men clubbed together"
an intricate knot tied by Gordius, the king of Phrygia, and cut by the sword of Alexander the Great after he heard that whoever undid it would become ruler of Asia
any very difficult problem; insoluble in its own terms