(1):

(n.) A concurence or general tendency, as of circumstances, to one event, as if by agreement.

(2):

(n.) A combination of men for an evil purpose; an agreement, between two or more persons, to commit a crime in concert, as treason; a plot.

(3):

(n.) An agreement, manifesting itself in words or deeds, by which two or more persons confederate to do an unlawful act, or to use unlawful to do an act which is lawful; confederacy.