What describes a contract where one party prepares the terms and it is not negotiable?

A contract where one party prepares the terms and it is not negotiable is best described as a Contract of Adhesion. This type of contract is typically created by one party, often in a position of power, and presented to the other party on a "take it or leave it" basis. The party receiving the contract does not have the opportunity to negotiate the terms, which can often lead to a lack of parity in the contractual relationship.

In essence, Contracts of Adhesion are characterized by their standardized nature and the fact that an individual often has little to no influence on the terms being set forth. This is commonly seen in agreements such as insurance policies, where the insurer lays out the terms and the insured must accept them if they wish to proceed.

In contrast, the other types of contracts mentioned involve different characteristics: Aleatory Contracts involve an exchange of unequal values, such as insurance policies where premiums paid may or may not result in a payout. Unilateral Contracts involve one party making a promise that the other party accepts by performing a specific act. Conditional Contracts are dependent on certain conditions being met for the contract to be executed. Each of these definitions highlights different aspects of contractual relationships that don’t align with the nature of a Contract of Adhesion.