A person who has special knowledge about the inner workings of a group, organization, or institution. / A person who is within an enclosed space.

plural of inside

plural of insider

(baseball, informal) A home run in which the ball does not leave the field of play; an inside-the-park home run.

(US, law, finance) Information obtained by or from a person in a position of trust (a director, an employee, a consultant) that affects the price of publicly traded securities.

Alternative form of inner diameter

(rugby) a back whose primary job is to create space for the outside backs outside him, i.e. the scrum-half, the fly-half and the inside centre.

plural of inside joke

present participle of inside edge

plural of inside edge