stipulation

(noun) (law) an agreement or concession made by parties in a judicial proceeding (or by their attorneys) relating to the business before the court; must be in writing unless they are part of the court record. Synonyms: judicial admission. Example: "A stipulation of fact was made in order to avoid delay."

(noun) an assumption on which rests the validity or effect of something else. Synonyms: condition, precondition.

(noun) a restriction that is insisted upon as a condition for an agreement. Synonyms: specification.